Well done on this original concept of the player losing his head, and the 2 phases that makes the gameplay change asking the player to adapt, I liked it !
I also liked the pixel art and the fact that the shot head rebound like that on the player/walls haha
What would be good I think is to add a feedback sound on the player getting hit. I sometimes didn't noticed I lost that much health and got surprised by my death :')
But tried again !
Thanks for sharing your work and game !