This is a fun prototype! Art-style is on-point, gameplay is fun and rewarding with the drops - I'm excited to see how you expand it.
The music is awesome, who wrote it? It's really well done and I think it fits the setting perfectly.
The only critique I have is I thought that the SFX didn't match the gameplay or visuals. I felt like the Wizards spell SFX needed more weight to it. I won't go into detail, but I think overall the SFX sounded a little too retro, and I think this game could really benefit from a more modern approach to the sound design.
That being said, I realize that it's a jam and sound is usually the last on the agenda. You accomplished a lot in one week and ended up with a fun and compelling prototype!