Defined by (no specification or reference implementation on file) Shoot-'em-Up, Arcade, dual joystick Commentary Gnarly game, but very hard. I especially liked the 3D effect on the intermediate levels with the staircases. (Even though it's awkward to control and far too easy to die on these.) The "word from our sponsor" interruptions are also quite cute. There is something coherent and unified about the design of this game that you don't often see in other games; you get the impression that it was crafted rather than simply produced. Well, maybe I'm overstating it a bit, but you get the idea.