definitely not winnable, but also definitely fun and impressive :D
An entry for TweetTweetJam - this is a game that fits entirely into 2 tweets (currently 560 characters).
It's sokoban, the classic game of shoving boxes around until you get them all stuck against walls-- or, if you're lucky, getting them loaded onto the truck (here denoted with a big orange X). Arrow keys move. Control-R restarts. Each game is randomly generated, probably not winnable, and actually has no way to detect if you've won or not. Have fun!