RectRot is a puzzle game that has you controlling a block in 40 levels of increasing difficulty. The goal is to reach the green portal, which must first be unlocked by collecting blue keys. Your block sticks to platforms, allowing it to move along walls and ceilings. The only way the block can detach itself from a platform is by shooting at it, which will cause it to fly in the opposite direction. You can destroy brown platforms by shooting at them. Your score is decided by the number of moves it takes you to get the block to the goal.