[coderjames]

For developing 2D games, I've found the combination of Love2D [0], Bump.lau [1], anim8 [2], and Gamera [3] to be extremely productive for me. This is a Lua game engine with additional libraries for collision detection, animation, and moveable/zoomable camera.

I'm an embedded C++ programmer by day so I've almost certainly done many of the things on the OP's list. It wasn't until I set C++ aside after 15 years or so and gave Lua a chance that I finally started making real headway on my Secret Agent Sam remake.

[0] http://love2d.org/ [1] https://github.com/kikito/bump.lua [2] https://github.com/kikito/anim8 [3] https://github.com/kikito/gamera

(Note: I'm not kikito, just an appreciative user of his work)