ImpactJS is a robust, well tested, and experienced HTML5 game engine. It continues to be maintained frequently and has a large supporting community that encourages the further development and refinement of the framework.
The ImpactJS framework has extensive documentation making getting started an easily guided experience. It is designed to work on all devices including mobile including iOS.
Ranked in these QuestionsQuestion Ranking
Pro Excellent collision detection system
Impact provides 2 types of collision detection; static and dynamic collisions. Both of which are easily integrated into game development.
Many plugins are available, including one called Impact++ which adds features like pathfinding and dynamic lighting.
Pro Level editor
Built-in map editor with support for tiling, collision layers, and actors.
Pro Extensive documentation available to support development
ImpactJS has an active user community that busily produces tremendous resources including videos, books, tutorials, walkthroughs and more. There are also comprehensive class documentation available.
Pro Truly cross-platform allowing developers to build for anything
Extending the reach of a game developed with ImpactJS is easy due to the cross-platform nature the framework. There are Considerations around performance, resolution and audio, however all can be appropriately addressed when in development. Works in the browser via Canvas, even on mobile. Easily translatable into a packaged app.
Con Not being maintained
Impact is not being maintained anymore. Last release is from 2014.