I think leaving the "old-school" out of the title doesn't do this justice. My first thought was, with modern engines, or even raw OpenGL that isn't that hard... I did it in a weekend for my "Advanced Computer Graphics" elective in college using OpenGL and that was 2008. But this is kind of cool... it's more of a tiny ray tracer and... well to borrow the title... old-school arcade game.
> it's more of a tiny ray tracer It's a ray caster, where the rays are sent out from the camera to intersect the map. With ray tracers, the rays are sent out from the light source, IIRC. Your point on OpenGL is valid, but that just removes all the learning from it. OpenGL does so much of the grunt work for you. This kind of old-school game engine is a great learning experience.
Not correct. I see this pedantry often, but it's factually wrong. If you look at the Wikipedia articles for both ray casting [0] and ray tracing [1], they BOTH describe the methods as sending rays from the camera/eye.
From what I can tell, the difference between ray casting and ray tracing is that in ray casting, only the primary ray is traced. The ray does not get reflected, refracted, or even traced to light sources for checking shadows. At most, surface normals are dealt with for lighting and texture mapping is applied.