Open Doors is a great game created by Kongregate user soapaintnice. The concept is deceptive simple: move your square box from its starting point through some doors to the destination marked by the X. Moving past a door’s pivot will open it, but some doors don’t necessarily open the way you’d expect them to.
The original Open Doors was published in 2008, and #2 was released just the other day.
Play the Open Doors | Play Open Doors 2.