I like the game, especially UI is very lovely made. I would gladly finish the game, BUT man, these flashes. I may, perhaps, be a bit photosensitive, so like at first I just didn't look at these flashes on boss death, but then comes the boss 5, which just constantly flickers when you attack him and on him I gave up, because it was unpleasant to look at the screen. So yeah, would be cool to have some kind of setting, which disables these flashes or something (for example Everhood has it, so both type of players, photosensitive or not, can enjoy the game). And then don't forget, that you need some kind of warning, that your game has such kind of stuff, cuz there could be people more photosensitive, than me.
For other small moments I noticed:
- Perhaps could introduce controls before first level start, like show the screen like you do with other levels. Yeah, I figured out by myself, that I can move with WASD and shoot with space, but I had a feeling, that maybe I'm unaware of some other controls, like maybe I have some shield ability or something and dev just forgot to introduce the controls at all.
- Bosses 2-5 felt a bit weak compare to first one, iirc 2nd can shoot laser and other ones just float. Could add some kind of bullet hell patterns to make it more interesting and increase bosses hp a bit.