CoolGames Design & Technical Guideline

Before your game is published, there are some design and technical requirements we have for your game. We’ve put together this document based on our years of collective experience developing, testing & publishing HTML5 games to the web, and beyond that to ensure your game is enjoyed by the largest audience possible.

If you have any questions about these requirements, please feel free to email your licensing manager, and if you have technical questions about implementation, e-mail

Our in-house QA team will validate these items (in addition to basic compatibility certification) before approving for launch and will reach out to you directly

We look forward to publishing your game!


Adaptive Display/Orientation

If your game is designed to be played in a portrait orientation (height is bigger than its width) then your game will need to have the ability to detect its orientation & the device being used (desktop or mobile). An expanded UI/screen for desktop users needs to be provided to enable users viewing the game in a landscape frame on desktop, and portrait view on mobile.

A good example of this implementation – Bubble Academy: //

Bubble Academy is a portrait designed game. When loaded on a mobile phone,

Bubble Academy is a portrait designed game. When loaded on a mobile phone, game will load as a portrait game, with the game board filling the horizontal space appropriately. However, when you play the game on a desktop PC, the game’s background & UI elements expand to fill the additional horizontal space.

No Visual Flickering Between Transitions

If your game transitions between screens (i.e. between the splash, the loading screen and then the game’s main menu), the transitions should be visually seamless. No blinking black screens or blank screens that cause a flickering sensation. The loading process should appear visually smooth to the player. The same holds for any in-game screen transitions.

Must Be Playable with Touch and Mouse

Our players play games on a wide variety of devices including laptops, tablets, phones and desktop PC’s. Your game should be designed to be playable on any of these platforms. This means mouse/keyboard input should work as well as touch input. Additionally, if your game displays on-screen directions, it should tell non-touch users to use the mouse/keyboard and touch users to use tap.

UI & Button Placement

Do not place important UI elements, buttons, or critical gameplay areas at the edges of the screen as these areas may be obscured by mobile browser UI (specifically on iOS) or the CoolGames Menu tab.


All games must have a high-score system integrated. At the end of each level the high-score should be shown and submitted to the SDK High-score pop-up.


Beyond the Design requirements outlined above, CoolGames requires that all games satisfy basic technical certification requirements. This is to ensure your game works on the broadest set of browsers and devices possible.

Game Code & Engine

Please submit your game with non-minified/ non-obfuscated code.

The game should not be built in GameMaker, Construct 2, GameSalad or Unity (basically any tool that builds the game in a scripting language and then compiles it out to JavaScript).

Fonts & Localization

If your game is being considered for localization by your licensing manager, your game will need to use standard fonts, loaded locally for text display and no bitmap fonts.

Additionally, if text strings in your game can be stored in a separate language/text file (preferably csv or json file) rather than directly in the game code, it will make localization a faster & easier process.

Operating Systems, Browsers & Devices

At a high level, your game should work on the following browser/OS combinations and the following hardware (equivalent or better)


IE/Edge Google Chrome Mozilla Firefox Safari Android Browser
Microsoft Windows Latest Latest Latest Latest N/A
MacOS X N/A Latest Latest Latest N/A
Apple iOS* N/A N/A N/A iOS 11.X N/A
Google Android N/A Latest N/A N/A Android 6.X

* – iOS does not allow non-Safari browsers. Even Chrome for iOS is using Safari webview to render web content

iPhone iPhone 6
iPad iPad 4 Mini
Android Phone Samsung Galaxy A5 / Samsung Galaxy J5
Android Tablet Samsung Galaxy A6
Laptop / Desktop (PC or Mac) 2012 or Newer

Feature Checklist

We run through the following feature checklist for each game. Make sure your game qualifies for the next features and we advise testing the game properly on multiple browsers and devices:

Type Test Description
Audio Can audio be muted/unmuted? Required
Audio Does audio pause/mute when browser loses focus? Required
Audio If audio does not work on a specific device/browser, are the audio buttons removed? Required
Text Does game text correctly align with UI? Required
Text Are words correctly spelled? Required
Text Does text make sense for the selected language? Required
Art Animations run smoothly Required
Art Game plays at the device resolution (i.e. does not display a super-tiny window when playing on a larger device Required
UI Make sure all game UI buttons work as described across all screens Required
UI There are no scrollbars open in the iFrame Required
Play Game behaves according to rules Required
Play Each game mode can be played to completion Required
Scoring Game scoring mechanism is working correctly Required
Scoring If points earned are displayed per action (i.e. a +100 displaying over a gem match), the total score adjusts correctly Required
Branding All links pointing to external pages are removed –  including more games button, developer page or any other out-links Required
Performance Game should play at a consistent framerate Required
Performance Game should load/start in under 10 seconds Required