Really rough, however I'm forgiving of that in the sense that it should stay to show how far you'll go in future with this.
Main issues are that A. Not enough tower spots. B. It starts right away with insanely fast and intense amount of enemies, forcing your into buying Archers only. C. There's no information on anything, towers, enemies, etc etc. D. The arrows are literally rotated wrong, use transform.rotation to fix the rotation of the projectiles to spawn based on the parent's rotation.
E.The map is incredibly limited, there's a 2 lane design here but the limits of the map size being so small provide basically no strategy.
F. A serious lack of variety of both attack towers, SUPPORT TOWERS (there are none) and enemy types.
G. Also Thumbnail isn't an accurate representation of the game.
Anyway, that's all, I'm curious to see how this grows in future.