I really loved the idea! I feel like you could really build upon it to create a unique and interesting puzzle game (eg. being squashed horizontally and then vertically could result in your player being smaller cube, or maybe more toggleable checkpoints to make some kind of an interesting puzzle).
Gameplay-wise, the dying and respawning was a little bit tedious. I get that it had be included to fit the theme better, but if you could move forward after being squashed, the gameplay would feel much smoother.
Also you really nailed the minimalistic aesthetics. Overall, great job! :)