Pretty well polished game with a fun variety of gameplay aspects. Writing was good, story was cool, and it ended at a natural place for a jam game. In general, I like when a jam game has a beginning and end, and isn't just the first part of something larger, but I think this is the next best thing. I was looking forward to more combat and cool moves though! I seriously thought I was going to be looking for 12 shadow monsters, which I wondered how you'd fit into a jam game.
A few issues made me confused - I turned on instant text, and I think perhaps I made the text move too quickly when Lucretia goes into the empty classroom after school. The movement route froze her in place after that and I had to restart and be more patient (thank you autosave). I also completed the tile puzzle, but the solution didn't trigger until I rotated one of the tiles 360 degrees. I'd also suggest you make the player semi-transparent while they are turning the tiles, since I had to step off a lot in order to see if it lined up (EDIT I saw you have another solution in mind already, which looks good to me). Lastly Lucretia's "kick" wasn't quite a kick. As always, I'd love to see some cool action sequences in there for moves.
Hope to see some more chapters, and well done jam entry!