This game is so good. I have no idea how it has this few ratings when it's this good. The inversion is super clever, and how things keep on escalating is excellent. The mechanics are introduced wonderfully, everything makes sense, and the difficulty curve is well-executed. Juggling all the different weapons, and all the enemy types, and protecting the food is difficult but not insurmountable.
The only real issue with this game that I see lies in the 'hub' world.
Either you should've committed to the using the mouse as your input and let the player click where they wanted to walk, or you should have let the player use an 'interact' button to enter the levels when the prompt popped up. Using the arrow keys to move, but the mouse the enter the level feels a bit weird. It also would've been nice to have WASD work in addition to the arrow keys. Both the arrow keys and the mouse (at least in the case of right-handed people like me) are on the same side of the keyboard, so I naturally use the same hand for both of them, when it would be nicer to use both of my hands for control, as is the case with WASD.