You play as a ghost named Sissel with the power to turn back time to four minutes before someone's death, and then possess the objects around him to prevent the victim from getting killed. It's a pretty unique idea, and I can't think of another game that's done it before. You start each puzzle without knowing exactly what your goal is, but as you flit around the room and experiment, Sissel will occasionally drop hints as to how the situation might play out differently. For example, in the first non-tutorial level, you have to keep a little girl from being kidnapped by an assassin. Sissel comments that the assassin wouldn't find her if she was under the couch, but she only crawls under the couch when her dog chases something down there. From there, it's up to you to figure out how to make that happen.
The game can be kind of slow. If you make a big change, you have the option of restarting from that point instead of the beginning of the four minutes, but you're still forced to go along with the natural flow of time. That means that if you're experimenting to figure out the right sequence of actions to take, you're going to end up watching the same events play out an awful lot.
Still, this is a neat idea, and the game does a good job of bringing it to life. Definitely give it a try if you're looking for a puzzle game with unique mechanics, a fun story, and colorful characters.