Doom is the classic id Software game that preceded Quake, now on its third (and most realistic) incarnation - or should I say carnage? - where you spend the whole first level in the dark with nothing but a pistol or a flashlight. Boring.

Some enterprising folk, however, have managed to port it to a Texas Instruments calculator and also to an iPod (more than once, actually), but these are mostly useless stunts.