Wow good job. I love your idea! I got stuck after I died against the birds.
- I love your core idea, if you haven't you should check out Space Station Silicon Valley. Its a bit dated now, but it plays to a similar idea. Also Cubivore might interest you.
- The player was forced to run back and forth each time they died, I'm not sure a great fix for this since you wanted each side to be distinct.
- A minor thing, but to fix the tearing you you'll want to only move the camera in pixel increments. Unity offers a pixel perfect camera, but its not great.
- I really loved all the different creatures you got to play.