Usability Concerns of Android Casual Game ... - IEEE Xplore

Science and Information Conference 2015 July 28-30, 2015 | London, UK

Usability Concerns of Android Casual Game Applications:Analysis and Improvements Jawaria Sarwar Khan

Fahim Arif

Athar Mohsin

Department of Software Engineering, Military College of Signals, National University of Sciences and Technology, Islamabad, Pakistan [email protected]

Department of Software Engineering, Military College of Signals, National University of Sciences and Technology, Islamabad, Pakistan [email protected]

Department of Software Engineering, Military College of Signals, National University of Sciences and Technology, Islamabad, Pakistan [email protected]

Abstract—For the game to be successful and for a good user experience, game usability and its interface usability is very important. Users now have a great variety of mobile game applications but their usability is not guaranteed. Among many other game applications, android casual game applications are very “in” these days. Bubble shooter concept based games are selected for this study, being the casual game applications. As there was no usability framework for these types of games, so usability questionnaire framework is developed to test their usability on android games audience. Secondly usability improvement framework is also suggested to improve these games and is also the outcome of the study along with the questionnaire framework. Keywords—casual game applications; usability engineering; human computer interaction; mobile computing; android smart phones; bubble shooter games

I.

INTRODUCTION

According to Neilson, games are the most widely used apps [37]. Android market is said to be almost on the top for gaming apps as it offers many free games that users have to pay for in other stores1. Similarly, for developers, games make up nearly 90% of the total android market revenue2. Along with free game apps, users also demand for their high usability/quality3.For the good user experience and game success, game usability and game interface are very important [5],[7]. But, due to the fierce competition and fast development of mobile games, usability in game design, seems to be ignored4. This can ultimately have the negative effect on the game success as well on the user experience. So 1 Maria Baeta (2014, Sept.9). “What’s the best platform for games Android, iOS or Windows Phone” [Weblog entry].Softonic.Available: http://features.en.softonic.com/whats-the-best-platform-for-games-androidios-or-windows-phone [Sept. 12, 2014]. 2 Taylor Stein. (2014, Oct.13). “Android Gaming Statistics 2014: A Worldwide Glimpse” [Weblog entry].Big Fish.Available:http://www.bigfishgames.com/blog/android-gaming-statistics2014- a- worldwide-glimpse/[Oct. 14, 2014]. 3 Muhammad Kashif (2013, Aug.13). “Mobile App Testing, Mobile Game Testing-Best Practices” [Weblog entry].folio3blog.Available: http://www.folio3.com/blog/mobile-app-testing- best practices/ [Jul. 4, 2014]. 4 Jens Peter Jensen. (2013, Apr.19). “Usability in Mobile Games: The Triumph of Bad Design” [Weblog entry].GA Game Analytics blog. Available: http://blog.game analytics.com/blog/usability-in-mobile-games-the-triumphof-bad-design.html [Feb.21, 2014].

it’s essential to thoroughly test the game usability before releasing it into the market. According to ISO/IEC 25010 software usability is defined as to which level, it is easy to learn, operate, access, help for user error protection, has good user interface aesthetics, and is recognizable to be appropriate [33]. For games, usability is defined as the level to which a player is able to learn, control, and understand the game [20] and to which extent the game is effective, efficient and satisfying for the user [10]. If game genres are seen, then casual games cover 35% of the total mobile gaming audience which is almost largest among other genres [21]. It is predicted that casual games and social games will remain the most popular genre at more than half of all games downloaded on mobile5. Similarly, mobile phones are "always-on-person," so casual mobile gaming is successful in filling free time [22]. It can be said that smart phones are a boost towards the popularity of casual gaming apps. These games are considered to be easy and fast to pick up and drop [18]. They are wide-ranging and have an ability to speak to a player’s need for fun and leisure [19]. According to many researchers, playing casual games have been declared as an increasingly popular leisure activity almost among all age groups and these apps are targeted at a mass audience [23],[24],[25]. Keeping in view the trend of casual gaming apps, five android casual games are selected which were developed and updated during 2013 and 2014. All the games are based on the concept of bubble shooter. The game concept is selected on the basis that it was previously developed for PC 6 and was very popular (due to its addictive mechanics) among all age groups i.e. children, teenagers and adults7.This game is shifted to the smart phone platform now. Due to the fact of variety of mobile game apps and their usability problems; bubble shooter game apps may also have the usability issues. These games 5 Steve Peterson (2013, Apr.30). “Mobile to be “primary hardware” for gaming by 2016” [Weblog entry].gamesindustry.biz.Available: http://www.gamesindustry.biz/articles/2013-04-30-mobile-to-beprimaryhardware-for-gaming-by-2016 [Jul. 4, 2014]. 6 (2003-2005).”March 26, 2001” [Weblog entry]. Bubble Shooter. Available:http://bshooter.com/news.html?pagewanted=all[Apr.25, 2014]. 7 “Bubble Shooter” in Wekipedia the Free Encyclopedia [Online],n.d. Available: http://en.wikipedia.org/wiki/Bubble_Shooter[Apr.25, 2014].

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will undergo the usability testing in this research and respective improvements will be suggested for them. This paper comprises of ii) literature review, iii) methodology, iv) results, v) results analysis and discussion and vi) conclusion and future work. II.

LITERATURE REVIEW

This research has adopted the technique of systematic literature review (SLR) [16]. Based on this method, the main work done on computer games usability, mobile/smart phone games and applications usability and mobile devices usability has been identified. Usability defactos and dejures are also reviewed to make the study more effective. Game design and evaluation heuristics were first proposed in 1982[11] having modules of challenges, fantasy, and curiosity. In 1989, usefulness of the general software application was defined as the degree to which the users believe that using the system would enhance their performance [14].The dejure IEEE Std.610.12 in 1990, defined usability the ease with which a user can prepare input, interpret outputs and can learn to operate a system or component 8 .In the same year Norman gave usability guidelines including good conceptual model, visibility, good mappings and feedback [31]. Neilson then (1993), provided software usability heuristics that are considered as the usability defactos [12]. Perlman [32], also proposed practical usability evaluation methods for systems including inspections and questionnaires. PHUE, is the online usability questionnaire majorly based on Perlman proposed questionnaire and to some extent focuses Neilson’s and Norman’s heuristics [36]. The dejure of ISO-9241-11 (199798), identified efficiency, effectiveness, and satisfaction as key attributes for a product to be used[34].Another ISO standard, ISO/IEC-9126 (2000-1), defined usability as software quality feature in terms of understandability, learnability, operability, attractiveness, and Usability compliance[35]. Barwood et al. (2002)9, started the 400 project to collect four hundred rules of game design to help designers make better games. Federoff (2002) used existing usability and game heuristics, and game designer input to develop a list of video game usability heuristics based on expert opinion [10]. Desurvire et al. (2004) developed a set of Heuristics for evaluating playability of games (HEP) based on the previous research and verified them empirically [13]. Mobile phone usability questionnaire (MPUQ), the first usability questionnaire for the mobile phone devices was developed in 2005[15]. It was first to be different from the generic software questionnaires of that time. The first most mobile games heuristics were proposed in [7] (2006), having three modules of usability, mobility and gameplay. It evaluated the games of type combat, adventure, simulation and puzzle. Then in 2007, heuristics were proposed which were effective in detecting playability issues in multiplayer 8 Laura Faulkner (2006).”From Ergonomics to Usability”[Weblog entry]. Usability Body of Knowledge.Available:http://www.usabilitybok.org/what-isusability/ergonomics-to-usability[May 29, 2014]. 9 Barwood, H. and N. Falstein. (2002, Mar.). 400 project [Online]. Available: www.theinspiracy.com/400_project.htm [May 28, 2014].

mobile games [9].Pinelle et.al [20] conducted a study on video game design in 2008. He presented ten heuristics covering usability features and described how common usability issues could be avoided. It was concluded that those heuristics were only applicable to game prototypes in the early development stage. In 2009, PLAY (Heuristics of Playability) was proposed for video games [6]. It was refined from HEP having major modules of game play, coolness/entertainment, usability and game mechanics. Work has been done on the usability and playability of mobile phone and web site based pervasive gaming applications [1] (2009). Heuristics of [7],[9] are used in many recent researches related to game usability including mobile game based learning apps in which content learning aspects were proposed[3](2010).In 2011,Dejure ISO/IEC 25010 has replaced ISO/IEC-9126(2000-1). It has defined usability as learnability, operability, user error protection, user interface aesthetics, accessibility and appropriate recognizability[33]. In 2012, content sharing mobile gaming applications [2], were studied by applying the existing usability and playability aspects. [5] made the revised list of usability heuristics for the computer games by directly involving the users. For the usability of touch screen mobile devices (2012), heuristics were proposed and evaluated, and it was concluded that if the heuristics are very specific they are expected to be hard to comprehend and apply [17]. In 2013, [4], Six different game categories (action, simulation, puzzle, arcade, multiplayer racing and multiplayer shooter) were studied in the light of heuristics proposed in [7] and [9]. New problems were reported (based on expert views), which were not present in these considered heuristics. In the same year another research has been done on casual mobile game apps usability focusing on elderly people of Brazil. The methodology adopted for the study was the survey that was designed on the basis of existing game usability heuristics. Since this study has the limited scope in terms of audience so it will be only helpful for the researchers and developers who are interested particularly with the game usability issues of elderly [8]. It is revealed from the above review that works particularly on mobile games started from the year 2006 and there is still a space to study these games. Work done up till now, is based on previous works done on computer/video games, usability of general software and the first most playability heuristics of mobile games. Regarding the mobile app genres it is clear that limited work has been done on the usability of casual mobile games. III.

METHODOLOGY

A. Heuristics Arrangement For the research, the usability heuristics of above defactos, dejures, computer/video games and mobile games are used. They are molded to study the smart phone games of casual genre (single player) having the concept of bubble shooter. Thirteen heuristics categories are sorted out from the above literature and presented along with the detailed heuristics and its sources in Table I. Heuristics that were not applicable to the study were omitted including heuristics related to game story, game

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characters and their customization. Similarly the replicated heuristics were also adjusted by considering them as one with TABLE I. Category 1.General ease of use

2.Game controls and less to remember aspects

3.Game feedback

their multiple sources.

HEURISTICS FOR USABILITY EVALUATION OF BUBBLE SHOOTER CASUAL GAMES Heuristics

Sources

Simple actions necessary for game play should be obvious and easy to perform

[5], [14]

Discover new/additional game features easily

[15]

Game controls should be intuitive and simple enough to learn to use quickly

[3],[4],[5],[6], [33],[12],[36], [7],[20],[17], [10],[13]

Use of game controls should not be frustrating

[1],[12]

Game controls should not need the manual/guide to learn

[1],[33] ,[15], [12]

The appearance of symbols/icons on game interface should give clues about their purpose

[5],[6],[15], [20],[10] ,[13]

The layout and menus should be intuitive and ordered so actions on them don’t need to be remembered

[6],[3],[4],[12], [36],[15],[7],[17], [33] ,[15]

Game should give the feedback so that game progress can be seen

[7],[20],[17], [15],[3],[4]

User can compare the game result/progress/score(may have the possibilities such as with the best ones he made and/or with other players result/progress/score)

[3],[4],[7]

Game should give the feedback /status information by showing score

[3],[4],[6],[15], [7],[20],[17],[10], [13] [15],[20],[17], [10],[13]

The score as a game status/feedback should be clear and visible

[1],[6],[15],[17]

Game feedback upon user actions must be immediate Game feedback should not interrupt with the play Game challenges and its solution strategy should be balanced

[6],[12],[36],[3], [7],[17],[10],[13], [33], [15] [6] [3], [4], [7]

Game should offer increasing challenging levels step by step

[1], [6],[13]

The game requiring new skills to solve challenges should be perfect

[6],[10],[13]

The game should be tough enough to try different tactics against it

[6],[13]

Game levels should not frustrate user by increased challenge which results in quitting

[6],[10],[13]

Game should be hard to master

[6],[10],[13]

The navigation between game menus and dialogues should be logical, consistent and least possible Pointers (help in navigation) should be clear and visible

[1],[3],[4], [15],[12],[7], [17],[10],[13] [4],[7], [36],[15]

Game should give the appealing feedback /status information by using music/sound effects/visuals/emotions

4.Challenge in game

5.Navigation in game

6.Entertai-nment,Attractiveness and engagement in game

The game should not have repetitive and boring tasks The game should be entertaining and reduce stress The game should be enjoyable to replay

7. Audio, Visual and Interface representations/settings for game support

[6],[7],[3] [3],[4],[6], [15],[7],[33] [10],[13]

The game should offer visually pleasing and engaging layout

[3],[4],[6],[33], [15],[7], [10]

Game’s audio should engage the user in game

[6],[10]

The game should give rewards/ power ups/customized options to user that engage him more deeply in the game

[7],[3],[4],[6], [17],[10],[13]

The user should not face any loss/penalty in score constantly for the same failure Game should be easy to learn to play, the first time user encountered with it and should be encouraging

[4],[6],[7],[13] [12],[3],[4],[6], [7],[10],[13]

Menus that are used for game settings, should be clear in the way that player don’t need to seek though menu after menu to search for a particular setting.

[15],[5]

The game interface must be independent of device interface for different operations (like sound control, menu, back button etc.) so user involvement must not be effected

[3],[4],[7]

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8.Errors finding/ prevention, recovery in game

The layout of the game interface should allow to always see the information/things needed (no extra irrelevant stuff)

[6],[12],[36], [17]

The game should allow skipping the unwanted content (non-playable, frequently repeating)

[20]

The interface should not interrupt user action or disturbs the game in any way

[6], [10],[13],[15], [5]

The pictures/interactive content on the screen should be of satisfactory quality and size

[6], [10],[13],[15]

The menu layers of a game interface should be least possible

[10],[13]

Game app should provide undo or redo options to recover/reverse the errors (if caused) while using game user interface

[3],[4],[33],[12], [7],[17],[10]

Game app offers clear and fast “emergency exit” options to leave the unwanted state selected by mistake The game app should offer adequate confirmations (to prevent errors) before the action is committed while playing (e.g. Are you sure to quit?)

9.Different user level support in game

10.Consistency in game and layout

[15]

Error messages in game should clearly show the problem if occur and offer the solution to it

[12],[36],[15],[17]

The game must provide enough information to begin play (initially)

[13],[6]

The game must be fun for user as a beginner player for this game The game must have different playing ways (modes) to win the game

[6] [6],[10],[13]

The game must have adjustable speed according to user need

[20]

The game must allow adjusting the difficulty according to requirement

[20],[10],[13]

Same terms, words or actions have one meaning and are understandable

[4],[12],[36], [7],[17]

The game levels should have a logical flow from basic to complex

[5]

Game play must be consistent which is liked by user

12.Help and documentation

13.Game goals

[12],[15],[6], [17],[10]

The game should not stop unpredictably

The user interface and colors must be according to the game

11.Game mobility and adjustment in unideal conditions

[12],[17]

[6],[17],[10], [13] [3],[4],[7],[15] [17],[10],[13]

The game should accommodate with the surroundings and with general health risks e.g. adjust sound, colors, brightness (low/high) etc.

[4],[33] ,[3],[7], [20],[17],[5]

Game should allow to save the game in different states (due to phone calls, other conflicting tasks e.g. bus/friend arrival due to which pause is needed )

[6],[10],[13]

Game and play sessions should start rapidly

[3],[4],[15],[7]

The help should be easy in use and must provide help for gameplay

[12],[19,[15], [3],[7],[4],[20],[17]

The game should provide help “during” play

[1], [6], [10], [13]

User should not have to rely on help guide again and again which interrupts the play

[6]

The “hints” must be of the level so that the beginner player for this game app can play

[5], [6],[10]

The game hints should not interrupt the play

[5], [6],[10]

Game goals must be clear The game should teach new skills before it is needed

[1],[3],[4],[6],[7], [10],[13] [6],[33] ,[13], [10]

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B. Data Collection Following steps were taken to collect data: 1) Usability Analysis Technique: The technique used to analyze games usability is usability testing as it gives direct and actual users input [12]. 2) Audience:It was found out that android gamers are nearly 20% from the age of 13 to 18 years. Almost 40% are from the age group of 19 to 25 years and 30% of players are of 26 to 35 years old. People from 36 years to onwards cover approximately 10% of the total android gamers 10 .So users were divided (both male and female),on the basis of these age groups. For apps testing, Neilson’s guideline was followed that five users are enough to test any type of software e.g. websites, PC or mobile apps etc.11. Audience was selected on the basis that they have an experience of playing casual games on their smart phones. Detailed audience distribution is given in Table II. TABLE II. Gender Male Female

13-18 5 5 10

AUDIENCE DISTRIBUTION

Age in years 19-25 26-35 5 5 5 5 Users per group 10 10

Total 36-above 5 5

20 20

10

40

3) Questionnaire: Data was gathered using questionnaires. It was mainly divided into two parts. First part has questions regarding basic demographic information. Second part has aspects/questions based on existing heuristics of Table I,to analyze the selected bubble shooter games, using Likert (type) scale. This scale is widely used to measure user preferences [26],[27] including the field of usability evaluation [30]. Ranges from 1-5 have been used, 1-Strongly agree, 2-Agree, 3-Neutral (neither agree nor disagree)/undecided, 4-Disagree, 5-Strongly disagree. With the help of this users rated the heuristic aspects according to their play. One open ended question was also given so that participants can highlight the additional improvements needed for the games. The questionnaire can be accessed from the web link as mentioned below: https://docs.google.com/forms/d/1JVPbeU52CbqLA8vgW md3rzKBqskuv3AU968YoAg3rE/viewform?c=0&w=1&usp=mail_form_link 4) Games for Testing:Games were based on the concept that player has to tap where he want the bubble and make a group of three to clear the screen. Different patterns were 10 Ben Frankel, Google Play Games team. (2014, June.2). “New Demographic Stats in Google Play Games Services” [Weblog entry].Android DevelopersBlog.Available:http://androiddevelopers.blogspot.com/2014/06/new-demographic-stats-in-googleplay.html [Jul. 19, 2014]. 11 Jakob Nielson. (2012, June.4). “How Many Test Users in a Usability Study?”[Weblog entry].NN/g Neilson Norman Group Evidence –Based User Experience Research, Training and Consulting. Available: http://www.nngroup.com/articles/how-many-test- users/[Jul. 22, 2014].

formed by the bubbles to make the game interesting. Games were different on the basis of the development companies/ developers, the playing modes and the features they offer. a) Egg Shoot by Eco game12:This game has three modes (Fig.1). In classic mode, player has to score by surviving as long as he can. Bonus points are offered if vibrating eggs get hit. In puzzle mode, eggs screen should be cleared with limited shots. In time mode, player will score on the basis of the time he takes to clear the screen.

Fig.1.

Screen shots of game Egg shoot

b) Dinosaur Bubble Shooter by Sun shine Apps 13: This game offers two modes (Fig.2). First mode has limited shots/bubbles. In second mode, arcade,balls move in descending direction and screen must be cleared as fast as possible.

Fig.2.

Screen shots of game Dinosaur bubble shooter

c) Bubble Shooter City by Loga Games 14 :It has two modes (Fig.3). In puzzle mode, limited bubbles can be used to clear the bubbles on the screen. In arcade mode, descending bubbles have to be cleared in a limited time.

Fig.3.

Screen shots of game Bubble Shooter City

d) Bubble Shoot Royal Deluxe by Srsdev15:It has three modes (Fig.4). In puzzle mode, player has to clear the screen with limited shots. In arcade mode, the level extends offscreen and the screen must be cleared before the level completely comes down. In Infinite mode, there is no shot or time limit. As the player play, bubbles randomly descend and make the game hard. The game also has special bubbles. 12 Egg Shoot [Online].Eco game, n.d.https://play.google.com/store/apps/details?id=com.ecogame.eggshoot &hl=en [Jul.30, 2014]. 13 Dinosaur Bubble Shooter [Online].Sunshine apps, n.d.https://play.google.com/store/apps/details?id=th.sunshineapps.dinosaurbu bbleshooter&hl=en [Jul.30, 2014]. 14 Bubble Shooter City [Online]. Loga games, n.d. https://play.google.com/store/apps/details?id=com.hillsmobile.bs&hl=en [Jul.30, 2014]. 15 Bubble Shoot Royal Deluxe [Online].Srsdev,n.d.https://play.google.com/store/apps/details?id=com.freega me s.bubbleshoot&hl=en [Jul.31, 2014].

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IV.

RESULTS

The collected data is presented with statistical means.

Fig.4.

Screen shots of game Bubble Shoot Royal Deluxe

e) Bubble Mania by Bubble shooter game labs16:It has two modes (Fig.5). In one mode, player has to clear the screen with limited bubbles while in arcade mode bubbles move downwards based on time and player has to score within this limit.

Fig.5.

A. Basic user information Users of i) age group and ii) gender were approached (as mentioned in Table II).The collected demographics were iii) Participant occupation and iv) the time usually given to play casual games on smart phones. In statistical terms, participants’ occupations comes under the nominal measurement scale being qualitative variable while playing time period comes under ratio measurement scale being quantitative variable. Frequency distribution is flexible with all variables of measurement scales to represent data [28], by mostly using frequency tables, bar charts etc.17. Bar charts are used here to represent the collected data.

Screen shots of game Bubble Mania

5) Conducting Survey:User survey was conducted in two parts during the months of August, September and October of 2014. Data was gathered in indoor and outdoor sittings/areas. Firstly, users were addressed about the purpose of research and their basic information was collected. Then in second part user responses were collected about apps. Before games evaluation, users were briefed about the evaluation process and basic concept that what the games are about. In addition they were asked to play all modes available in games. Two to four users were considered in every session. They were provided with the android smart phones i.e. Q Mobile X11 (android version 4.4.2) and hTC desire hd A9191 (android version 2.3.5).Games were already installed in the phones. Every participant had to play with all five games and then had to fill the questionnaires. Small breaks were taken during the evaluation sessions. Participants, themselves, told their experiences about games after playing them which were noted down as well. Fig. 6(a) and 6(b) are the snapshots taken while conducting the usability evaluation of games.

Fig.7.

Users Occupations

Fig.7. shows that almost 33% of the audience was students. Approximately 13% were related to accounts. Teachers, IT specialists and pharmacists were 15% each. Business men and house wives covered 10% in total.

Fig.8.

Casual games play time period

It was evident that most of the audience usually play mobile casual games between 6-15 minutes (52.5%) and for less than or equal to 5 minutes (27.5%) as shown in Fig.8.

(a)

(b)

Fig.6. (a) Users playing and assessing the games (b) Researcher conducting research 16

Bubble Mania [Online].Bubble Shooter Game Labs,n.d.https://play.google.com/store/apps/details?id=com.nghiadoanvnnstud ios.bubblemania&hl=en[Aug.02, 2014].

It is inferred from the above collected information, that casual games are famous among people in almost all age groups (who play games), gender and occupations, as discussed above, and it is mostly played for short intervals. 17 (2013, Jul.3). “Statistical Language - Frequency Distribution”[Weblog entry].Australian Bureau of Statistics. Available:http://www.abs.gov.au/websitedbs/a3121120.nsf/home/statistical+l anguage+ frequency +distribution [Oct.28, 2014].

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It was discovered from the survey that these demographics were not so closely related to the ‘casual game apps playing aptitude’ of participants. It means that though users were different in age, gender, occupation etc. but they all like to play (usually) the casual games on smart phones. On this basis all audience categories are considered, equally important to analyze the usability issues of casual bubble shooter game apps and to suggest the improvements for them. B. Games usability testing results 1) Heuristics results:Games usability responses for heuristics were collected by using Likert (type) scale. Ordinal measurement scale is recommended to analyze the data collected in this way [26], [29].Nonparametric statistical methods should be used for ordinal data 18 ,[29], and modes19,[29],or median20 can be used for this purpose.Modes are calculated from all responses against heuristics to analyze the results (Table III). There were 40 responses per app making 200 responses in total against each aspect. TABLE III.

RESPONSES RESULTS AGAINST HEURISTICS OF QUESTIONNAIRE FRAMEWORK

Category 1: General ease of use Simple actions necessary for game play are obvious and easy to perform App1 App2 App3 App4 App5 CM 3 2,3 3 3 3 3 Discovery of new/additional game features is not easy 4 4 2 2 2 2 Category 2: Game controls and less to remember aspects Game controls are intuitive and simple for you to learn to use quickly 3 2 2 3 2 2 Game controls are frustrating with difficulty to support to play the game 3 3 2 2 2 2 Manual/guide is consulted to learn the use of game controls 4 4 4 4 5 4 Purpose of symbols/icons on interface is clear from their appearance 2 3 3 3 3 4 The layout and menus of game are familiar and ordered so the actions on them don’t need to be remembered. 2 2 3 3 3 3 Category 3: Game feedback Game shows the progress appropriately as a feedback 2 3 3 2 2 2 Game result/progress/score can be easily compared with the best ones you made and/or with other players result/progress/score 3 5 4 4 5 4,5 Game feedback/status information is supported by appealing music/sound effects/visuals/emotions etc. 3 3 3 3 5 3,4 Game shows score as a feedback/status information 2 1 5 5 5 5 Game feedback is shown immediately on your actions by using sounds/visuals/emotions 1 2 2 1,2 2 2

18 I. Elaine Allen and Christopher A. Seaman. (2007, Jul.). “ROUNDTABLE STATISTICS Likert Scales and Data Analysis” [Weblog entry].Quality Progress. Available:http://asq.org/qualityprogress/2007/07/statistics/likert-scales-and-data-analyses.html [Oct.30, 2014]. 19 NCS Pearson. (2014). “Level of Measurement” [Weblog entry].TutorVista.com.Available:http://math.tutorvista.com/statistics/levelsof- measurement.html [Nov.23, 2014]. 20 See Footnote 19.

The score as a game status/feedback is not clear and visible 3 3 1 1 1 1 Game feedback interrupts the play 4 3 4 4 4 4 Category 4: Challenge in game Game challenges and its solution strategy is balanced 2 2 2 1,2 3 2 Game offers increasing challenging levels step by step 2 2 2,3 1,2 3 2 The game requiring new skills to solve challenges is perfect 3 3 3 2,3 3 3 The game is tough enough to try different tactics against it 2 3 3 2 3 3 Game increased challenge caused frustration (you want to quit) 5 4 5 4 5 5 Game is somewhat hard to master 1,2 2 3 2 3 2 Category 5: Navigation in game Game menus and dialogues navigation is logical, consistent and least 1,2 2 3 2 2,3 2 Pointers for navigation are clear and visible 3 3 3 2 3 3 Category 6: Entertainment, Attractiveness and Engagement in game The game is boring and have repeating tasks 4 3 3 4 3 3 The game is not entertaining 4 3 3 4 3,4 2 The game is not enjoyable so you would not like to replay 4 4 2,3 2 2 2 The overall visual layout of game is pleasing and engaging 3 2 3 4 4 3,4 Game’s overall audio content is engaging 4 4 3,4 4 4,5 4 The game give rewards/power ups/customized options which has engaged you more deeply in the game 3 2 5 4 5 5 There is no loss/penalty in score constantly for the same failure 2 3 3 2 3 3 Game was easy to learn to play in the first moments and was encouraging 3 3 3 3 3 3 Category 7: Audio, Visual and Interface representations/settings for game support Menus used for game settings are clear, so you don’t need to seek though menu after menu to search for a particular setting. 3 2 3 3 2 2,3 The game interface is independent of device interface for different operations (like sound control, menu, back button etc.) so game involvement is not effected 2 3 2 2 3 2 The interface layout allow you to always see the things needed (no irrelevant stuff) 3 3 4 4 4 4 The game allow to skip the non-playable or most repeating content 2,3 3 2 3 3 3 Interface has no interrupt on user action or disturbs the game in any way 3 2 4 4 4 4 The pictures/interactive content on the screen is of suitable quality and size 3 3 2 4 4 3,4 The menu layers of a game interface are least 3 2 2 3 2 2 Category 8: Errors finding/prevention and recovery in game Game app provides undo or redo type options to recover/reverse the errors (if caused) while using user interface 3 2 3 3 3 3 Game app offers clear and fast “emergency exit” options to leave the unwanted state selected by mistake 2 3 2 2 2 2 The game app offers sufficient confirmations (to prevent errors) before the

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Science and Information Conference 2015 July 28-30, 2015 | London, UK action is committed while playing? (e.g. Are you sure to quit?) 2 2 1 2 3 2 The unpredictable game hang is experienced 4 4 4 4 4 1,2 Error messages in game does not clearly show the problem if occur and no solution is offered to it 3 3 4 3 3 2 The game provides enough information to begin play (initially) 3 3 2,3 3 3 3 Category 9: Different User level support in game The game is fun for you as a new player of this game app 2 3 3 2 3 2,3 The game has different playing ways (modes) to win the game 1 3 1 2 1 4 The game speed is according to your need or can be customized as needed 2 3 4 4 4 4 The game allows adjusting the difficulty according to your requirement 2 3 3 3 3 3 Category 10:Consistency in game and game layout Same terms, words or actions of game have one meaning and are understandable 3 3 3 3 3 3 The game levels have logical flow from basic to complex 2 2 3 3 2 2 The user interface and colors used are according to the game 2 2,3 4 3,4 4 4 Game play is consistent which is liked by you 2 3 3 2 3 3 Category 11: Game mobility and adjustment in unideal conditions The game accommodates with the surroundings and/or with general health risks e.g. adjust sound, colors, brightness (low/high) etc. 3 2 2 2 3 2 Game allow to save the game in different states (due to any conflicting task e.g. bus/friend arrival etc. due to which pause is needed ) 2 2 3 2 2 2 Game and play sessions starts rapidly 2 2 2 3 2 2 Category 12: Help and documentation The game help is easy in use and provides help for gameplay 3 3 3 3 4 4 The game provides help “during” play 3 3 4 4 4 4 You don’t have to rely on help guide again and again which interrupts play 3 3 3 3 3 3 The “hints” are of level so you as a new player for this game can easily play 3 3 3 3 3 3 The game hints do not interrupt the play 3 3 3 3 3 3 Category 13: Game goals Game goals are clear 2 2 2 2 2 2 The game teaches new skills before it is needed 3 3 3 3 4 4

participants from the game. The collected data, separately for the games is summarized in Table IV. TABLE IV. 1. x x x x x x x

2. x x x x x

3. x x x x x x x

4. x x x x x x

REQUIRED IMPROVEMENTS

App1-Egg Shoot Eggs/balls were not swapping. Power ups must be present. The long arrow (ball pointer) was a bit distracting and hides the balls at times. Aiming was poor as the arrow gets wide and extends so far that person can't see where he is trying to hit. There was no reason for the blocks present in puzzle mode, it was annoying. No background music was there and feedback sounds were not so appealing. Score board seemed to be wrong as the players’ names cannot be seen who has made the high score. App2-Dinosaur Bubble Shooter The background continuous sound was not according to the game, seemed to be of racing game. Colors of balls were not distinguishable, same colors get mixed like orange and red. Arcade mode was a bit difficult and was extremely fast. Balls were not exchangeable that were used for shooting. There must be some free type mode in the game in which you don’t have time limit. App3-Bubble Shooter City Music did not match with the game. Same shades of balls like light green and dark green, made them difficult to distinguish. The content about bubbles description was difficult to read as it was very small and its color mixes with the background. Arcade mode was present on the menu but not working. It was annoying. No bonus points were offered by the game. The winning feedback sound was inaudible due to background music. Ball exchanging feature was discovered at the end of game. It was very small to see. App4-Bubble Shoot Royal Deluxe Help content had very small font size and was difficult to read. The bar shown on the bottom was confusing .It seemed that it had to do with the game pace but actually it had no purpose. Arcade mode was very fast. Music was not like to be the part of game. Ball exchanging feature seemed to be not present in the game but discovered after some play. It was very unclear on the interface. New game controls were not known initially, discovered after some time. Different game options like sound were difficult to select because of the minuteness. No score board was present. The feedback sound on user action was not alone audible from the background music.

Note 1: Boxes for modes have first five for App1- Egg shoot, App2Dinosaur bubble shooter, App3-Bubble shooter city, App4-Bubble shoot royal deluxe, App5-Bubble mania and the last one is for the CM-Cumulative mode.

x

Note 2: The CM column having bold numbers depicts that maximum apps violate the aspect and Apps modes columns having bold numbers depict that which app(s) individually violate the aspect.

x x

2) Required Improvements discovered from open ended question:The questionnaire had open ended question as well, to cater the improvements and aspects required by the

x The game hangs on some instances. 5.

App5-Bubble Mania

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Science and Information Conference 2015 July 28-30, 2015 | London, UK x x x x x x x

Arcade mode was a bit speedy. Blue and grey balls were hard to distinguish from each other. No background music was present in the game. No bonus points and power ups were offered Aiming was not good balls shoot in the wrong direction. The feedback sound was annoying. Leaderboard feature should be present in the game.

V.

RESULTS ANALYSIS AND DISCUSSION

A. Usability violations by games To analyze the results of heuristics, the repeating aspect (issue present in maximum apps) is considered once while the non-repeating aspect (issue not present in all apps but present in some apps) is also considered as a violation. Modes representing 1-Strongly Agree, 2-Agree,4-Disagree and 5Strongly Disagree are considered for analyzing the issues, as 3- Neutral leads to the undecided option. Aspects found to be violated by the app(s) are shown in Table V. TABLE V. 1. x

VIOLATED HEURISTIC ASPECTS

General ease of use: Discovery of new/additional game features should be easy.

7. x

Consistency in game and layout: The user interface and colors should be according to the game.

8. x x

Help and documentation: The game help should be easy in use and provide help for gameplay. The game should provide help “during” play.

9. x x

Errors finding/prevention and recovery in game: The game should not stop without the intent of user. The game should show error messages if it stops working and solution must be provided for it.

10. Game goals: x The game should teach new skills before it is needed.

B. Usability improvement framework Based on the violated heuristic aspects and participants suggestions, usability improvement framework is proposed for the ideal bubble shooter game app. The framework recommendations are discussed in Table VI. TABLE VI. x

x x 3. x x x x 4. x x x x x

5. x x x

6. x x

2. Game controls and less to remember aspects: Purpose of symbols/icons on interface must be clear from their appearance. Game controls should not be difficult to support the game play. Game feedback: Game result/progress/score should be easily compared with the best ones user made and/or with other players’ result/progress/score. Game should give the appealing feedback /status information by using music/sound effects/visuals/emotions. Game should give feedback/status information by showing score. The score as a game status/feedback should be clear and visible. Entertainment,attractiveness and engagement in game: The game should be entertaining. The game should be enjoyable so users like to replay. The overall visual layout of game should be pleasing and engaging. Game’s overall audio content should be engaging. The game should give rewards/power ups/customized options that engages the user more deeply in the game. Audio, Visual and Interface representations/settings for game support: The layout of the game interface should allow to always see the information/things needed (no extra irrelevant stuff). Interface should not interrupt the user action or disturbs the game in any way. The pictures/interactive content on the screen should be of satisfactory quality and size. Different User level support in game: Game should have different playing ways (modes) to win the game. The game speed should be according to the user need or can be customized as he wants.

x x

x

x x x x x

x x

x

x

x x

USABILITY IMPROVEMENT FRAMEWORK RECOMMENDATIONS

The game should show score as a feedback concurrently and it should be clearly visible with the contrast background and foreground color. Balls used for shooting purpose, should be exchangeable. As users play these types of games for short bursts so game play facilitating features e.g. ball exchanging and new game control etc. should be made known to the user as soon as he starts or before he starts the game. The feature icon for game play (here ball exchanging feature), should be of contrast color with background, larger in size and should be symbolized as it speaks for its purpose. Balls should have completely distinct shades so that they can be distinguished easily. Same or alike shades should not be used. Bonus points should be given to the player to make the game interesting and engaging. For player’s entertainment, enjoyment and engagement in game, the game should offer power ups as rewards. The visual layout of game should be pleasing and according to the game genre. Plain colored background should be avoided. To make the game more entertaining and engaging, player should be given customized options. So, options are proposed including match more than three balls and different visual backgrounds. The game should offer the background music which must be engaging and according to the game genre. The feedback sound on user actions, including winning, losing, ball shooting should be separately audible from the background music and should be appealing. Visually, the feedback should be made appealing. The use of some character that act and the background that shower is suggested to show winning and losing emotions. The character will also depict emotions on user actions to give more pleasing feedback effects. The game should have different playing modes such as time/arcade mode, puzzle mode and free type mode in which player neither have the time limit nor the ball limit. Arcade mode speed should be adaptable according to the user. Different game options/tabs should be larger in size so that they are recognizable and their selection/click becomes easy.

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Science and Information Conference 2015 July 28-30, 2015 | London, UK x

x x x x x x

x

Any type of reading content whether it is help or bubbles/balls description, should be readable by having the large font size and the contrast color that does not mixes with the background. Things having no purpose for game should be avoided on interface. All menu options present on the interface should be working. If they need to be opened with certain score or levels limit then they must be presented to user when he fulfills that needed limit. The game should help the user during play to aim / shoot the ball in the direction as the player wants. The aiming pointer should be thin that it cannot hide the balls on the screen and player can see where he is trying to hit. The game should not hang during playing but if this happens then proper error messages with recovery solution should be provided to players such as restart the game or report problem. The working and real gamers score board feature should be present in the game so the results can be compared with others.

VI.

CONCLUSION AND FUTURE WORK

This study is focused on the usability of bubble shooter casual game apps for android smart phones. As no framework existed previously to evaluate these games, so the questionnaire framework is presented, developed from existing game and usability heuristics. Five game apps were analyzed by the players and upon their responses the improvement framework is suggested. Outcomes of this research i.e. the usability questionnaire framework and the usability improvement framework for bubble shooter android game apps will be helpful for the developers, designers and the researchers of the related domain. The future work includes the detailed design of the ideal bubble shooter game application based on the suggested improvement framework. REFERENCES [1] Jegers, K., "Investigating the applicability of usability and playability heuristics for evaluation of pervasive games," The 3rd International Conference on Internet and Web Applications and Services, ICIW '08, Athens, pp.656-661, 2008. [2] Somasundaram Kothandapani, Dion Hoe-Lian Goh and Khasfariyati,”Influence of playability and usability in a mobile human computation game”, Proceedings of 32nd International Conference on Distributed Computing Systems Workshops, Washington, D.C., USA, pp.75-78, 2012. [3] Zaibon, S.B.and Shiratuddin, N., "Heuristics evaluation strategy for mobile game-based learning," The 6th IEEE International Conference on Wireless, Mobile, and Ubiquitous Technologies in Education (WMUTE), Kaohsiung, pp.127-131, 2010. [4] Sarmad Soomro, Wan Fatimah Wan Ahmad, and Suziah Sulaiman,”Evaluation of mobile games using playability heuristics”, Lecture Notes in Computer Science, vol.8237, pp.264-274, 2013. [5] Michael Brown, “Evaluating computer game usability: developing heuristics based on user experience”, in press [6] Heather Desurvire and Charlotte Wiberg,”Game usability heuristics (PLAY) for evaluating and designing better games: the next iteration”, Proceeding OCSC '09 of 3rd International Conference on Online Communities and Social Computing: Held as Part of HCI International, pp.557-566, 2009. [7] Hannu orhonen and M.I.Koivisto,“Playability heuristics for mobile games”, Proceedings Mobile HCI '06 of 8th Conference on Humancomputer interaction with mobile devices and services, New York, USA, pp.9-16,2006. [8] Luana Giovani Noronha de Oliveira Santos, Lucila Ishitani and Cristiane Neri Nobre, “Casual mobile games for the elderly: a usability study”, SBC - Proceedings of SB Games, XII SB Games – São Paulo – SP – Brazil, pp.127-136,2013.

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