[ShadowMarth]

Hmm, as it so happens the people that are making Portal made a somewhat less impressive game with roughly the same theme called (could be wrong with the spelling here) Narbacular Drop.

Edit: Score:
http://www.nuclearmonkeysoftware.com...culardrop.html

Edit again:
I recorded some nifty video of Narbacular Drop, so check it out on my GS profile.

http://www.gamespot.com/pages/profil...HExwTX_5bMLvT8