I have Stimpy's Invention and you're right, it's an excellent game.  Just wish the music was a little better, less GEMS-sounding.  I've been thinking of acquiring all the 8-and 16-bit R&S games & doing a review/comparison kind of thing.  I'm considering maybe skipping the gameboy titles though.  They seem very poor in comparison to even Quest for the Shaven Yak on the GG, which I have fond childhood memories of.