Really nice entry
I particularly like the sound design, while the main level music is a bit minimal the boss theme and game over jingle are cool.
Spritework is also good and i like the variety of enemies environements and spells, and i'm not sure cause it went a little fast but i suppose you added a sort of megaman element to the spells (by that i mean i think the mushroom boss took more damage from the fire spell) which i like.
If i had to nitpick i'd say main issues i had were that i couldn't figure out how to interact with the shopkeeper, and that in the starting segment, walkable ground doesn't pop enough from the background.
Other than that it's fun to play, the boss was a cool bit and i like how defeating him is what unlocked a new ability through the environement rather than the character.
Good job especially for a solo effort with no external assets at all :o