I'm quite liking the game, although I haven't been able to make much progress due to the second stage's difficulty. The amount of projectiles is a bit nuts, frankly.
However, my main issue is how unfair the visibility feels. This game is tagged as a bullet hell, which I believe makes it incredibly important to be able to see your enemies at all times.
As the game is right now, enemies are hard to see before you enter a room, and still hard to see until they get closer to you, due to the shading effect, (which also appears to apply to enemy bullets?!?) So, if bullets come from the other side of the room before I can predict them, that feels...
Well, really unfair.
That said, some of these rooms are so big that your enemies literally are on the other side of the room, meaning they're offscreen.
Also, I somehow got sucked through a golden portal after killing the first boss this one time, with a whole bunch of neat rewards, but I have no idea how I did that, and there was nothing to indicate that I did something special to deserve it in contrast to my several other runs. What's up with that?