I've always been a sucker for possession as a mechanic for puzzle games. Even with the run button I would say the default move speed is a little on the slow side, but the actual puzzle mechanics all blend together super well and most of the AI seems to work as intended. Some of the later puzzles get really intense, and the requirement to possess and the fact that repossession can kill an NPC really adds to the sense of urgency and thinking on your feet.
Very well done :)