These are courtesy of the kids over at Pixelation's forums. Last year, they ran a little contest. See who could come up with the best mock-ups for a remake - or demake - of a game crammed onto the original Game Boy. While some are unrecognisable, and a few are only "OK, I guess", the rest are "totally awesome, I guess". Especially the BioShock one. There's a few highlights below, with the rest of them to be found at Pixelation's site.
Mockup Frenzy #3: Game Boy De-Makes! [Pixelation, via Boing-Boing]