Look up how raycasters work, I've written a lot of them, you can write one in a few hours if you know how they work. F. Permadi has a great tutorial. I think there are a couple of them on pygame.org too.
Hope that helps, -Luke
How would I go about making an old style shooter, kinda like Wolfenstein 3d or Doom? Well, actually I've never played either, but I've seen screenshots.