When comparing Crafty.js vs Ren'Py, the Slant community recommends Crafty.js for most people. In the question“What are the best 2D game engines?” Crafty.js is ranked 37th while Ren'Py is ranked 39th. The most important reason people chose Crafty.js is:
Easy to learn, based on Entities and Components, the later being class-like objects that entities inherit.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Eventbinding
Easy to learn, based on Entities and Components, the later being class-like objects that entities inherit.
Pro Javascript
Pro Modular
Has open function binding systems, allowing easy creation of custom components.
Pro Cross-platform
Available on Windows, Linux, OSX, iOS and Android.
Pro Active and friendly community
Pro Reasonably good at creating puzzle and point-and-click games
Cons
Con No IDE
If you like having some huge GUI akin to Gamemaker, Unreal, Unity, etc, Crafty is not for you.
Con Not for every genre
While technically capable of creating 2D games in any genre, Ren'Py excels in creating visual novels and has a reasonable feature set for creating puzzle and point-and-click games. Other genres are best tackled by other engines.
Con Outdated Documentation and official built-in tutorials
Unfortunately, you will have to hunt relevant info on how Ren'py script works. The Ren'Py dev has the working tutorials on his Patreon, other than that you might as well just code in Python.