[Suicide Junkie]

I've had something like that happen to me.

After a minute of running, semirandom crudules start popping up.
I got the impression that it might be a memory leak causing data to spill over into video ram. Eventually hit would go past the bottom of the screen, and set the resolution to randomness, at which point it is game over.

Tossed the video card, and it is now fine.