Cool use of the 1bit theme. I couldn't memorize the fully grow stage of each plant, but I figured if it large enough, it is probably ready to be harvested 😄. Now that I think more about this, you could also let the player harvest early but reward a lower score. But anyways, I can totally see this potentially turning into a fun little couch co-op!
A quick tip: The character moves faster diagonally. This can be avoided by just normalizing the move direction vector.