MONSTER_C 

So, what exactly is Monster_C?  Well, good question! Let's have Cade, our programmer at LLC, explain:

"It's a homemade 2D game engine written in C using OpenGL 4.1 and GLFW. It tries to be as data oriented as possible and is working on being slim and more straightforward to use. It is currently in progress and very unstable so use at your own risk."