Addictive and stylish!
However, I think not being able to retry the same boss is a significant flaw. I'm sure every version of the fourth boss has some solvable pattern, but since you need to fight three other bosses before retrying and you might get a different version the next time, there's no good way to learn what the pattern is! I think I understand why Survivor and Hunter are balanced the way they are, and they seem like well-designed modes, but adding another more casual play mode with same-boss retries would make the game easier to get into.