Really? I feel like löve is just amazingly well designed, both in terms of API, and fundamentals. The basic concept of luajit + c++ core is nice, then the API is so straightforward and consistent that you can basically guess most method names and they do what you expect.

What is it missing? I'm honestly racking my brains here trying to think of stuff I've tried to do that was unexpectedly hard, and I can't think of anything. Maybe passing large arrays of vertexes to be drawn can be awkward.