Enjoyment: 4/5. You got a LOT out of these squares. For all the issues mentioned below it's notable that I kept playing almost until reaching the actual end of demo. (At a certain point I died but I didn't see what had killed me, and this was after several attempts getting back to the point with the disappearing/reappearing red squares. It's now occurring to me it was probably a quantum red square :) )
Execution: 2.5/5 rounded to 3. A bit jank just...to move, for me, for some reason. I'm sorry if this was just your luck but it was moving with some amount of camera-jerk. There were also some hitbox issues--it wasn't entirely fair-feeling getting hit in a lot of places. If you got rid of those alone this would probably go up 2 full points
Sensory: 2.5/5 rounded to 2. Coherent and generally inoffensive!
Metroidvania: 5/5: Honestly this feels pretty standard stuff for a minivania.
Minimalism: 5/5: Honestly this embraced the theme super-well. I'm not sure you got everything you were going for but I think you got at minimum the visuals.