The Last Boss Is the Only Boss in the Game That's Invincible

The only really original boss is the last boss and he's up in my opinion he's the only one that actually has genuine challenge like the other ones it just the only real challenge from the other boss fights is like can you tell when the boss's i-frames or not because they give you no indication of when they're invincible. It was a little frustrating but so to me king yeah king k-rules was much more sensible I think as a kid  I'd have to wait for him to take his crown off that's the only time you can hit him. But at least the game tells you this is what you do and sticks with it did.