Don't need the high-end graphics to have a good time? It may not look like much, but 8bit Killer is an old-school throwback to the birth of first-person shooters. Collect a variety of weapons across several levels; open doors and shoot anything in your way. Now mind you, nobody's confusing this blocky FPS with Crysis, but it's got enough style where it counts.
So go forth and shoot pixelly bad guys while grooving to chiptunes.