Interresting, but the OpenGL setup is not necessary?
Why not?
The author is handling sprite rendering entirely on the CPU, he's only using OpenGL to put a bitmap on the window. Little bit unnecessary.
GLFW+GL provides a portable way to do this though. Otherwise you'd need to mess with platform-specific window systems.
(something like minifb would be a more minimal option though: https://github.com/emoon/minifb)