This is a fine crafted and well executed bullet hell experience!

I love the way you've expanded the sprite set to your need in the construction of the game and how you've integrated it to the UI you are using. Also, you've picked a really good font that matches the vibe real good.

You did good with the diverse enemies and patterns, it made the game feel dynamic and challenging even it being enclosed in such a tiny playing area.

Enemy friendly fire was a shocker and I really enjoyed it. I was able to use the enemies' formation to my advange and sorta lign them up so that they shoot one another hahah

Music is good, but I feel something a bit less modern and more 8bit would fit the whole design even better!

Lastly, I felt the progression curve was a bit too steep... I'm not the best gamer hahah but the first enemy after the tutorial was already trouble. It works, don't get me wrong, but you might want to think about lowering the difficulty progression and making the player develop their skills durring a few more lvls before getting to the boss.

But anyways, this is awesome! Keep up the great work :)