Originally posted by: Shadowknight
The cowboy hologram game someone mentioned above. After that, Duke Nukem 3d. It wasn't true 3D, more like 2.5d. Monsters weren't 3d but the levels were sort of 3d.
The technological term is parralax scrolling, IIRC. The visual trickery can be easily seen if you enable mouselook and look up at a building, then pan to the left or right.