Interesting game. The elephant in the room is the art, which looks phenomenal in terms of style, animation, and color scheme. It's clear a ton of work went into the animation and it has a great Devil May Cry flair to it. Unfortunately, the music is compressed and distorted so heavily to the point of being really distracting. Similarly, I found this game lagging quite a bit with Ruffle. Put together, these two things really broke the immersion.
The actual levels between bosses struck me as unnecessary. They're short, the mob enemies are annoying, and the platforming is stupidly easy. I can sort of understand that they're meant to tutorialize the jump attack and rolling, but you could just as easily have had one tutorial introduce all of these mechanics and then had a boss rush. The player's moveset isn't that big to begin with and the bosses really are the meat and potatoes of the game. I never quite understood the healing mechanism. It looks like you can heal twice per level, and an infinite number of times during boss fights, but with cooldown? It looks like the thing that flies around you indicates if you can heal, but it would be nice to know how many heals you have left, or what your cooldown is rather than just having a binary "canHeal" indicator.
I found the bosses to be frustrating if only because of the lack of telegraphing (however I did really like that each boss had two phases.) For instance, I didn't even realize it was the head that was damaging me during the first boss fight for quite some time. I kept taking damage when the enemy didn't seem to be attacking and got confused. The 2nd and 4th bosses were fairly easy after recognizing this, but the 3rd boss in particular can be quite annoying. He has a tendency to teleport right on top of you, and the flame pillars that shoot across the bottom can sometimes activate right after you jump, making it such that you don't have time to jump again before they activate. The telegraphing is also pretty subtle, especially if you're looking at the boss rather than the platform on the bottom.. Why not make their eyes have a bigger glow, or some other more obvious effect? The lightning attack can also be confusing, as the warning strike looks like an actual attack. It took me a while to train myself to remember that the small strike was a warning for a larger strike. Perhaps if it were a single beam instead of two separate ones this would be clearer to the player?
Overall a pretty fun action game. With better framerate, crisp audio quality, and a clear boss rush mode, this could feel a lot cleaner.