ImpactJS vs Duality

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.

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.

Works with Box2d physics library, comes with all worthwhile elements for actors built in.

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.

The full source code is available on GitHub, where the framework is actively developed. All of the editor, core and plugin code is written in C#.

Duality includes a powerful visual editing system that can be used for previewing, integrating, editing and testing game content.

Because both Core and Editor are completely plugin-based, Duality not only incorporates a clean and modular design, but is also very extensible - even if it wasn't Open Source. In fact, most of the standard editing capabilities comes in form of Editor plugins.

It can be configured to serialize all data in a text-based format, which has been structurally optimized for version control systems.

It has been used in a production environment without burning the place to the ground. Supposedly artist-proof editor workflow with an API for tailoring the system to fit your team.