Neat concept.
Upgrades affecting both the player and enemies was a cool idea, but most of the time it just made upgrading feel pointless or less satisfying - I feel like there could have been a better balance there.
There were upgrades, but the movement did feel a bit sluggish. And the fact that it cancelled your movement forcing you to release and repress keys was really annoying/confusing.
I also found the music kind of hard to listing to, and sfx were fairly basic.