Cool concept! I was considering making a platformer about dying and coming back to life too!
I initially couldn't find the key in the dashing level. I had not seen the key due to the camera, and i did not figure out there was a key until the camera finally panned to the right! Game felt a little short, and I was hoping there would be more puzzles involving the dying mechanic!
Also: i don't like having to press K to die, it's too far away! And the corpse does not spawn in the place i expect it to spawn.
Good job on making a game!