Robotron is probably the best classic arcade game ever made. It's not my favorite, though I do love it heaps, however, I think it is the best made one. It's unpatternable, it's fast paced, it's fair, it can be played a variety of ways when you get too good at it (marathon or fixed lives style + high diff), it has a control scheme that was pretty unique at the time, it has a good risk/reward system specifically interesting for fixed life games, etc.
