I’m thinking about entering LD13 depending on what the theme turns out to be. I haven’t done a full LD yet, just 2 mini-LD’s. I wanted to use my standard C library functions for OpenGL, Portaudio, Ogg/Vorbis/Vorbisfile, and my GUI. There isn’t any game logic routines or structures as per the rules. It’s a collection of sound, text file, opengl drawing, and string tools for C.
I wasn’t sure what I have to do or if there is some type of time limit, but anyway here is a link to the library code. It’s mostly a conversion of some old SDL stuff I liked to use. I moved away from SDL lately though and have been using GLFW.