A game you want? A difficult one you say? Well get yourself here.
The idea of Putty Puzzle (from Kevin Glass's troublingly named Coke And Code) is to merge and move the blocks until you can reach a target. Level 1 will talk you through it all. Then level 2 will leave you feeling slightly scared.
Testament to this game: having played it for a while, as I started typing this I became concerned the words would fall down the page because there was nothing underneath them. Okay, testament to my going insane, perhaps. Anyway, free webby goodness. Thanks Indiegames.