I'm not sure i understood the treasure room riddle, i think i kinda did, though i found how to reach the end of the level, but for the next step i had to try like 4 times before the first door would actually let me through.
Anyway i reached the end of the story, which was cool ;)
The music loop is a bit short like some people said but it is sufficient i believe, it gives a good atmosphere to the game. The SFX could use some more work but they sure are of decent quality.
The graphics are really polished, good job !
If I were to give some advice i would say to work on the level design primarly, especially since the playable area is not what you see, i kinda played all the levels walking against everything i could.
Also the hitbox of the player against spikes is kinda huge, maybe consider reducing its size.
Overall you did a great job, congrats !