Nice idea! I love the sprites for this game!
This could definitely be expanded more into larger puzzles, with lots of room for more mechanics. Maybe something like being able to place gold pieces from yourself to momentarily lure the hero somewhere, or maybe having to avoid the hero casting spells and attacks at other enemies.
The audio effect for when you completed a level seemed a bit weird, I don't know if it was for the audio theme of the game, but it sounded like it breaks at the end.
Overall a nice game!