Haven't played on the higher difficulties yet, but it was pretty easy on the lower difficulties. 1cc'd on Beginner and Standard with little difficulty, will try the other ones soon. The accomplishments affecting your ship's weapons and bombs add some nice replay value. Maybe this is just the lower difficulties, but the bullet hell bits give you a bit of a deflector shield, so it makes the game pretty forgiving. Even if you don't normally play shmups, you should be able to reach the end and beat it without much trouble.