Xybots

In this game you run around in a 3D maze shooting the evil xybots. In some levels there are warp exits that let you skip a few levels. I usually tried to show them, but I didn't take them because I wanted to include all levels.

You can get money to buy things like a map or weapon improvements. Things usually only last one level before you have to buy them again. I ended up using all my money exactly, which is essentially what happens.