That was awesome! I loved the game! I just barely managed to beat it with a score of 368.
The gameplay was great! It ramps up pretty quickly but that's ok for a game jam game. The music is awesome! The sound effects are also fantastic and so is the art!
In terms of feedback: I would've loved a way to see what each party member does while I'm in the shop so I can compare with what the shop is offering. I also would love a short description for the items while in the shop so I don't have to just pick them and see what they are. I know you said you kept UX minimal to push the player to try things, but this is just my personal opinion ofc.
Overall the game is awesome, well done!