The Digital Eel guys recently decided to release it as freeware, so cool, check it out.
You remember Snake, right? If you're as old as I (half a sec, need to find the bedpan), you probably remember it as a little game that's been implemented for everything from the TRS-80 on up... and if you're not quite as antiquated, you played it, and maybe still do, on your Nokia mobile phone. Little worm crawls around a screen, you hit the arrow keys or directional keypad to change the direction in which it moves, it gets longer over time, and if you run into yourself or a wall, game over.
Pretty simple gameplay, but surprisingly compelling, given that simplicity.
Now imagine that same basic gameplay, with a whole series of power-ups and randomly appearing obstacles you need to eat to get bigger and get to the next level, with trippy psychedelic graphics and a techno score that would probably be danceable except that you have to keep your fingers on the keyboard to play, which doesn't give you a lot of freedom of motion for dancing.
This either is your kind of game or it isn't... But if it sounds like it might be, it's only 2 megs, so it's a quick download.