A very neat little game. I think the score adds a lot of value in the form of replayability; perhaps you can make a leaderboard like the other games in the jam. Are there any differences between characters? If not, it would be cool to add some. Is the light mode hard difficulty?
The main menu has Zs popping over it, so it kind of gets in the way of reading it. Although the learning curve is not steep, a good tutorial is always show-and-tell, not just tell-tell-tell. A little relaxed background music would be top. I imagine there is a max score, that should be indicated. A fullscreen would help my eyes.
I liked having a moment of panic when everything turned on at once. 8.2/10, I didn't see any feet...