I have a soft spot for the D'Avekki series of FMV games. They have a knack for new-weird world building with acting that walks the delightful line of camp and immersion. Dekker, Shapeshifting, and Dark Nights form a strange trilogy of intrigue and tone with strong production values. The Shapeshifting Detective has a fairly linear plot with these little optional branches that extend the fiction of the people and the setting, designed so you can run it a few times and learn something new. The killer is randomized, although guides or multiple playthroughs can make it painfully obvious who it is within minutes. It is not the deepest game in a mechanical sense, but it's a very charming vibe that I think about fondly.
It does run on Steam Deck, but at the time of this review, there is a glitch that causes a few frames of each video clip to flicker between what was playing and what should be when a new clip begins to play, like it couldn't queue up the right position in the timeline. Once the clip has been playing for more than a second, it will look correct. It's distracting and obnoxious, but it won't stop you from finishing the game. However, because the game is nothing but video clips strung together, you're going to be seeing that glitch hundreds of times. I haven't had this issue in the Switch version or my desktop PC.