Also why do you need a 2D game library? Why not link your own external dependencies (OpenGL, SOIL, FMOD, freetype2, etc...). Also Lua is very important for games development, most game developers use Lua for scripting.
Why not use sfml ??
It is not a game library but a graphic library..
Howvere, it is good
(It does not come with gravity built in tho...)
(There are many add on for it...thor is one that is game library add on for sfml)