Pros: The graphics and music are really good.
Cons: Unfortunately, there's several things going on that drag this game down, despite the pros.
1) No visible hitbox/pixel? That's kind of important in bullet hell games.
2) No keyboard control option, and the mouse controls are rather bad. The character seems to only sort of move to the mouse location rather than precisely moving to it. It also seems to move more slowly toward the mouse position when the mouse is close by, but faster when it's far away. This inconsistency is...awkward. Even with a visible hitbox, I don't think these controls would allow for the delicate maneuvering required when hundreds/thousands of bullets are on the screen.
3) The rate of fire (initially) is really bad. I guess it's just my personal opinion, but it's not very exciting when I have to focus more on making sure my slow, autofired shots will connect with something than avoiding enemy fire.
3) Too much like Bullet Heaven overall, but not as polished. Now I liked Bullet Heaven, but it's nice to see different games try different things to make them stand out. By essentially cloning Bullet Heaven, you're giving players a mediocre version of an existing game rather than a new and interesting experience with familiar elements.
So not bad. Assuming you really did create these art assets, I can safely say you've got a bit of talent. Try applying it to something that is more uniquely yours and you'll be well on your way to creating quality games.