Very nice pixel art and sound :) Gameplay was interesting and the different traps were challenging but well balanced.
A couple of suggestions:
- There's no need to come back after picking a soul. You can just suicide and go back. Maybe you could punish the player by dropping the soul.
- Create a distinct background for the walkable area and outside of the map boundaries.
- The hitbox of the feet and the spikes was sometimes a bit unpredictable, I'd try to tweak that.