I don’t think I’ve ever seen an RPG Maker game in a game jam before… That distinctive style makes this stand out a lot. I also was expecting a lot more timeloop mysteries in this jam, but yours was the first I played, so I enjoyed it! I like the large cast of interesting characters, and the variety of cars. the train felt full of life and fun to explore.
My main critique is I thought the mystery/puzzles themselves were a little flat. The appeal of a train mystery is usually that you’re trapped in a small space with a bunch of people, so you know all the narrative players and have to figure out what each of them know. It ups the tension because you know that someone you’ve met on this train is the culprit/is hiding something, and you’re all stuck together trying to figure it out.
In this game, the solution to the mystery was just that there’s a demon, which isn’t all that satisfying. Plus, some guy just told me that flat out. I didn’t get to figure out anything myself, and no one on the train had any interesting information to deduce. I also thought the puzzles themselves involved a bit of busywork - take item A here, get item B there, etc. That kind of basic adventure game-style puzzle would be fine if the mystery itself were more engaging, but I would suggest integrating some mechanics directly related to deduction as well.
Side note - the looping mechanic was a fun tie-in to the plot, but I wish it did more gameplay wise. As-is, it was kind of just a nuisance which teleported me to the start every five minutes. Most characters didn’t even reset their dialogue. I bet there are ways you could use the ability to loop to give the detectives unique opportunities to gain information. (Just as one suggestion, maybe certain characters follow the same patterns each loop… so you can apply your knowledge from previous loops to figure out what they’re up to.)
Overall - this was a really charming time! Good work!