Very cool concept! Iwas very curious what a "final boss generated from the player's own move" would mean and I really like the interpretation of the theme.
I'm not a fan of the instant death. It feels a lot like a die and retry ad that makes some parts a bit frustrating, especially when I jumped into the eye at the end of the boss fight because I didn't think it would hurt me. I would also say that some of the level design looks a bit messy with all the camera lights and lasers overlapping.
The platformer physics feels very nice. I like the character movements and the dash. I would prefer the shooting to be on a keyboard button since you don't need to aim with the mouse. I noticed you could shoot with the keyboard after completing the game and it should probably work like that by default so that people playing on a laptop don't need a mouse or use the trackpad.