Just caught up now, and gotta say, I love this game, and I love the characters. I actually can relate with Raymond a lot, which I'm sure says something about me, but I don't know what!
-Spoilers-
The loop element definitely gave me strong Higurashi/Umineko vibes, which I like. Handled differently enough that it's also fairly fresh. I also love the relationship between Ray and Jack. I wasn't expecting Jack to go full yandere for Ray, but honestly it only made me root for their happy ending more!
As for some things I've noticed, during the second loop, the statue that was potentially used to kill Zack in the first was already gone. I don't know if that was intentional, but if it is, it could lead some credence to the killer remembering things between loops.
The other is those interesting tarot cards I found lying around... Makes me curious what their significance will be in the long run. I imagine it may play more into the supernatural aspects of the mansion, perhaps. But I am eager to find out later!
I don't have any concrete theories yet... I think what's more important for me right now than finding out who the killer is would be to first have a better idea of the rules. For instance, whether someone being believed dead would be enough to count for rhyme, or if the person has to truly be physically dead. The former definitely opens up possibilities for the killer to hide among the dead, a la the Alice theory.