Investigate a nefarious serial killer, solve dastardly, dangerous puzzles, and poke your partner in Parallel Experiment, a point-and-click adventure for two players. It’s a mixture of escape room and noir mystery, taking you through the supernatural underground of Krakow and featuring stylised comic book-inspired visuals.

The second entry in developer Eleven Puzzles’ “Cryptic Killer” series, this title follows 2023’s Unboxing the Cryptic Killer but with a larger scope, containing roughly three times as much content, unlockable minigames, and a postgame free-exploration mode. Famous fiends for a co-op adventure, Luke and I donned our detective hats and kept pen and paper handy as we delved into this point-and-click puzzler.

The Cryptic Killer must be caught in 24 hours, and only detectives Allison “Ally” Abernathy and Steven “Old Dog” Kowalski are skilled enough to track him down. The story in Parallel Experiment is surprisingly dark for a multiplayer-only game, delving into violence, family trauma, and the occult fairly regularly. It’s told through textboxes and comic book panels that add a stylistic flair to the world, in addition to featuring full voice acting. There’s a diverse array of accents, and the quality does vary, but for the most part, performances are solid and add weight to the drama. A little too much drama for a two-player game, maybe – we found it difficult to take the heavier moments seriously while shit-talking over Discord.

As a dedicated cooperative experience like Split Fiction, you need to take on Parallel Experiment with a second player. The initial setup is straightforward and pretty seamless, allowing for cross-platform play between PC and mobile devices. Right away, you’ll be faced with a choice of who to play as: the headstrong and capable Ally, or the grizzled and jaded Old Dog. There’s a decent amount of exclusive content between the two, with unique dialogue choices and puzzles encouraging diehard fans to replay as the other character. There’s not a ton of intricate characterisation, but the pair get enough screen time that you grow to like them over the course of the adventure.

There are some really neat ideas in Parallel Experiment’s puzzle rooms: an abandoned store tasks you with reviewing surveillance footage for discrepancies, a bastardized pinball machine has you dragging a ball-bearing back and forth with a magnet, and there’s even a basement workshop that requires you to pass tools to each other through a hidden drawer to repair a Morse-code inspired lightbulb machine that hearkens back to Stranger Things. At their best, these are fun and challenging cooperative experiences that tickle your brain and reward you for working as a team.

Other puzzles are invariably hit-and-miss. For roughly half of the game, Ally and Old Dog explore locations together, meaning both players will be solving the same puzzles on the same screen without any real need for collaboration. One player can simply carry the pair through these segments, removing a lot of the unique satisfaction from working together. These puzzles also tend to be weaker, allowing for brute forcing without their main premise ever really revealing itself.

While cross-play with mobile devices lowers the barrier for entry, it also means that all puzzles in Parallel Experiment need to be solvable by interacting via mouse or touchscreen. This isn’t a big deal for the point-and-click sequences, but eventually you’ll be moving the detectives around in third-person via clicking (and at times, a virtual joystick). These gameplay segments end up becoming less about cerebral puzzle-solving and more about learning to navigate the jank of cumbersome, limited controls. It doesn’t help that Ally and Old Dog’s walking speed is painfully slow. A particularly frustrating section saw Luke and me shifting mirrors back and forth for several minutes, having mentally solved the puzzle ages ago and being forced to suffer through its execution. The controls also make most of the unlockable minigames tedious experiences rather than rewards for exploration.

Of the additional mechanics featured in the game’s marketing materials, we found none of them really outshone the core puzzle mechanics: you’re able to open an overlay that lets you draw on the screen at any time (I used this once and then forgot about it); you can cooperate in dialogues and “interrogate” a suspect (which kind of just resulted in watching a progress bar go up); and you can click on the other player to poke them and make their screen shake (which is admittedly very good).

That being said, we found more to like in Parallel Experiment than not. Exploring Krakow and solving cryptic puzzles as a team is a blast, and the five or so hours you and your partner spend scratching your brains feels satisfying enough without ever overstaying its welcome. There’s a healthy dose of “I’m a genius” moments mixed with many “I’m an oaf”, and in spite of some jank, there’s plenty to enjoy here for puzzle fans.