Michael Nørskov points me in the direction of this. It stars the elephant from Achievement Unlocked and is a metagame tinged piece of platform puzzling. It’s called This Is The Only Level. And it is. But it’s an awesome level and some of the puzzle solutions worked into it are plain brilliant. Others are funny. The best are both. Saying any more would spoil ’em. You really should play it.
More of this sort of thing