Thank you for the feedback!
I know that it's hard to know when you get hit, but theres wasn't enough time to fix that. I thought of the screen flashing red, or the ship sprite getting partially destroyed. I will work on an update to the game after the voting period ends.
Adding human health is a good idea, maybe if the bacterias don't get killed it depletes the health. It's true that the theme just fits the visuals, not the mechanics, next time I will try to merge those things togheter.