I think this one might be my favourite so far! The theme implementation is genius, it looks really nice and its genuinely super fun to play! In fact I was super disappointed that there wasn't any sort of endless free play :(
I guess my main suggestions would be:
1) Add some background music (sadly the current lack of music will hurt your final rating)
2) Add endless free play; I just wanted to keep going man.
3) Somehow alert the player if there are enemies or shapes. It was really difficult to know where to focus my attention though I guess for the enemies you could argue that player is intended to stay so that they contribute to all lanes. But if you do that, you miss out on a lot shapes; maybe just automatically add shapes to the player's inventory instead?
Those are very minor improvements; there's not much to improve in regards to the main gameplay loop. Because of that, I would love if you were to add more maps, enemies, etc; there's a lot of potential here, so i'd love to see what you can do :)