The Past Within Review (Wirdjos)
As this is Rusty Lake's first co-op entry, the puzzles are understandably less complex. Instead, the focus of the game is on communicating the various symbols and codes your partner will need to solve their puzzles and vice versa. Only one sequence in the 1 to 2 hour affair uses a timer to up the stress of trying to translate an input and, while it is fail-able, it is also infinitely repeatable. So don't worry about having to find someone you have a near psychic link with before getting started, fumbling is part of the experience.
Despite being a bit shorter than a Rusty Lake title and more on par with one of the studio's earlier Cube Escape games, you'll probably want to play through The Past Within at least twice. Once to see things from the Past's perspective and another from the Future's. Thankfully, there's an alternate puzzle solution mode to avoid memorizing to much too quickly and cheating yourself out of the full deductive process.
The same should be said about deciding to play the game alone. Considering its nature, it does seem possible to get through it without a partner(I think there's already a guide to just that effect), but most of the fun and the intended course of the story depend on indulging in the difficult task of trying to reach out to someone similar but still very outside of yourself. Take that away and you're only getting half of what The Past Within has to offer.