I just got this game available on Steam called "5D chess with multiverse time travel". It is chess but with time travel and alternate timelines. It follows the "branching timelines" theory of time travel. So you cannot change the past. Once you make a move it is fixed. However, you can send a piece back in time which automatically creates a new alternate timeline or you can send a piece to another alternate timeline. For example, you can send your queen back in time, creating a branching timeline with two queens. But the first timeline will have no queens anymore. The tricky part is figuring out how to check mate in 5D because now check mate requires that the king in every timeline be mate. So if a piece could capture the king by traveling to a different timeline or by going back in time, then it is mate. So you have to worry about a piece moving to a square that puts the king in check back in time or in another time line. Also, all pieces seem to move like the king when time traveling to a parallel timeline. So a knight can capture an adjacent piece when moving to a parallel timeline. This can be confusing at first since we are not used to pieces moving like that. If you love time travel, then this game might be for you because it uses chess to let you really play around with time travel and alternate timelines. It can definitely get crazy if you and the other player time travel a lot. You can create dozens of alternate timelines that you have to figure out. You can get yourself in a real messy time war! The guy in the video is super confused but at least it might give you a sense of what the game is like. I am definitely enjoying the game a lot.