Phaser vs Impact

Phaser keeps things simple and as such is easy to use by beginners.

Thousands of example are on the Phaser website, which show everything you could want to do with Phaser.

If WebGL is unavailable, Phaser automatically switches to HTML5 canvas.

Built specifically for mobile web browsers.

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.

Built-in map editor with support for tiling, collision layers, and actors.

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.

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.