Very clean little game! I can see an expanded version with different ores that have different effects and i think it'd be fun.
Nice graphics and satisfying animations, good sound design. It's a little short, but that's to be expected for a jam. My only criticisms would be the goblins' hitboxes are a little weird and the spikes look very similar to the ores, so i couldn't tell what was damaging me at first.
Check my submission out if you have the time!