The premise behind Shiftlings is you're on an intergalactic reality show and are basically just traveling around completing tasks so people can watch you and go "ooh". Pushing gas back and forth in that tube allows the dim-witted space custodians to change size, one growing big and getting heavy while the other stays normal. The big 'un won't be very mobile during this time, but he can use his size to his advantage, shoving heavy things around and interacting with bits of the crazy space environment that being small just doesn't allow one to do. Puzzles stretch out across 50 levels and five different environments, all of which are perfectly suited for both local and online co-op for two players.