Very nice pixel art, music and game mechanics! I like how you took VVVVVV's mechanic and changed it to a puzzle game instead. I've seen the "use your corpses to go forward" mechanic a few times, but you did find creative use for it.
I wish there were more puzzles with the first character, and maybe some where you switched between the two during a level. Maybe a third character as well.
I would've preferred to press R to restart rather than Esc -> mouse click.
The boss fight was okay, and looked cool, but no idea what he had to do with the story. I liked seeing his jaw drop when I beat him.