The theming and aesthetic here are pretty strong, much stronger than these escape room type games tend to be, and it has an undeniable character to it that I do appreciate. However the actual second-to-second gameplay isn't the best.

A co-op puzzle game that doesn't require a connection between the players is an interesting idea and great for accessibility. But I feel that this setup does rather hamstring tPW's potential a fair bit. You spend a lot of time entering passcodes to let the game know that you and the other player are still in sync, and the game ends up feeling quite back-and-forth; after every puzzle you solve, you end up having to wait for information from the other player, and there really aren't many times when you are solving puzzles simultaneously.

That all being said, I do really appreciate the game having two sets of puzzle solutions. In asymmetric games like this it seems obvious to me that many players are going to want to try both sides, but that second playthrough can often feel rather flat when you both know all the answers. Having two sets of solutions doesn't solve this entirely, you can't recapture the part of the game where you have to figure out what's even going on, but it's such an obvious step that I'm surprised I haven't seen other co-op escape room games do it before.

The Past Within ends up being a game with good vibes and good ideas on paper that don't really translate into anything that memorable or special. It's fine for what it is, but I would recommend checking out games like Operation: Tango, Unboxing the Cryptic Killer or the We Were Here series before settling for this.