When I was still in high school, I built a simple ray-casting engine. All it really does is display a two-dimensional grid as if the viewer were "inside" the grid looking around. You might like it. It has a large and colorful maze, and it is surprisingly easy to get lost.

One can freely edit the BIGSTUFF.TXT file and change the walls of the maze in an instant. The numbers represent the desired colors of the wall, and the character "M" represents a mirrored surface (a feature that the Wolf3D engine did NOT have).

The ray-caster, of course, has no textures, has a choppy frame rate, and it doesn't have a chance in hell at netting a "Game of the Year" title. But if you are a pragmatic sort of person, you will realize that my time and resources were limited in high school. More than anything else, this project was a scientific and mathematical experiment, and a quite successful one at that.