Got all the way to the end with the key and couldn't figure out what where to put it. I dragged it onto the door but I must not have go it in exactly the right spot. So I spend a good five minutes rechecking the room and trying to get the square out of the box thinking maybe it goes into the part on the door. If you have it zoom on the door, make it on a part you can use the key on. That or increase the size of the area it can be used on.