When comparing pygame vs ImpactJS, the Slant community recommends pygame for most people. In the question“What are the best 2D game engines?” pygame is ranked 14th while ImpactJS is ranked 51st. The most important reason people chose pygame is:
Pygame uses Python as its scripting language. Python is widely considered one of the easiest languages to grasp even for beginners.
Specs
Question Ranking
Pros
Pro Easy Python syntax
Pygame uses Python as its scripting language. Python is widely considered one of the easiest languages to grasp even for beginners.
Pro Very easy to understand
The API is very straightforward.
Pro Good canvas system
Pygame has a drawing system that allows the user to create and draw on an unlimited number of canvases.
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 Excellent collision detection system
Impact provides 2 types of collision detection; static and dynamic collisions. Both of which are easily integrated into game development.
Pro Extendable
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 Optimized
Works with Box2d physics library, comes with all worthwhile elements for actors built in.
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.
Cons
Con Very basic
Pretty much just a wrapper for SDL.
Con Messy documentation
The docs are messy, and some basic functions are infuriating to work out. There's even some places in the documentation where it's clearly wrong about how a method is called/what the arguments really do.
Con Deathly slow
Con Outdated
Pygame uses a really old version of SDL and is missing some of the features developed for SDL2.
Con Nonexistent community
No good forums, wiki, or other ways to reach other Pygame developers.
Con Pygame is a language, not a game engine
Physics, AI, networking, and input are not supported.
Con Hasn't been updated in years
Hasn't been updated in years.
Con Inactive
The last update was in 2014.
Con Cost of $99
While most HTML5 frameworks are offered as free open source projects, ImpactJS has a one time cost and no free option.