Probably my favourite computer game of all time is Commander Keen 4: Goodbye Galaxy -- you jump around a lot, collect things, and shoot anything that moves -- brilliant! Although, the game is spoilt by the inclusion of an underwater level where Keen becomes so slow, he can't get out of anythings way, and you get eaten by a big, stupid looking fish, so I actually prefer to play episode 5 which is all set on a space station with not a fish in sight.
However, times move on and those old games won't play in Windows 7 (or even XP), until I discovered the delights of DOSBox, which magically brings all those old games back to life. But still, once you've played them umpteen times, and used the cheat keys to discover all their secrets, the novelty can wear off. But Keen is not dead!
While I've been busy playing Plants vs. Zombies instead, there appear to have developed an whole community of amateur programmers who've been taken those old episodes of Commander Keen and modified them to produce new episodes! So now there's hours more nostalgic fun to be had -- just nip along to their official forum to download them: keenmodding.org
