Nice visual style. The tutorial is a bit long, only the most important things should've been explained. When you get 4 allies, the game gets so easy that you could play it indefinitely. This is mainly because all enemies come from the right and you can just destroy them as soon as they spawn. Also, the enemy spawn rate doesn't increase , so the difficulty always stays the same. Cool idea and nice mechanics, but I wish the balance was a bit better. Other than that, good job!