CHICKEN Scheme has excellent FFI support, so it was previously possible to use SDL2 from CHICKEN Scheme — possible, but not convenient or straightforward. I have made an effort to create programmer-friendly, convenient, thorough, and well-documented bindings. These bindings take care of the annoying low-level C stuff for you, so you can focus on making your game.
Although the version numbers for these libraries are only 0.1, they are ready to start using now. Some features have not been implemented yet, but it is already possible to create many types of games, even 3D games using OpenGL (when combined with the gl-utils or opengl egg, for example). Several demos and example programs are available to help you get started. Large backwards-incompatible changes are unlikely, but there may be small tweaks and fixes to the API if problems are discovered. There may be some bugs, but they will be fixed promptly if you report them to the issue tracker.
I also intend to eventually create bindings for other libraries, such as SDL2_ttf (for text rendering), SDL2_mixer (for sound effects and music), and SDL2_gfx (for shape drawing and image transformation).
In related news, there is a 7-day Lisp Game Jam coming up the first week of January. I will be creating a new example game using these bindings, and hanging out in the IRC channel (my handle is “jacius”) to answer questions about the bindings, CHICKEN Scheme, and SDL in general.