My one regret is not adding some sound effects. Probably wouldn't have even taken very long. Definitely had ideas for other enemies but in the end didn't really have the time to make them.
As far as the spells go, my idea is this is probably the most spells you would get within one dungeon, although the fireball would probably come from a mini-boss so that you can open the vine walls and progress to the final boss, and then there would ideally be a mechanic that required using the fireball spell to beat it. Likewise I tried to make it so the boss incentivized staying away and using the ranged spell. Originally planned on programming the boss to stay away from the player, but ended up just using the same random logic as the bats and then having the fireballs aim for the player, meaning if you're closer to the boss, it's harder to dodge.
I'm definitely going to be going back to this one soon. I plan on restructuring a lot of it, mainly because I realized too late that my rooms were going to be asymmetrical with the doors off-center. Hope you check it out when I've released a new version (I'll be leaving this version up as a jam version for posterity's sake.)
Thanks for playing and thanks for your feedback :)