Awesomely hard
I'd have to say this is one of the toughest games I've played on NG and I like a good challenge. Hand drawn animations are my favorite type. Only thing that made me gave you a nine is the ending. Even though you lost the first ending you did due to unforeseen complications, I still have to dock ya for it. I recommend that you polish the ending that you have.
To all those that are complaining about the difficulty of the game here's what I say. It's a game that you learn how to play, learn how to fight the boss and then kick his wooden butt into next week. Once you get that.. he is much easier than you think.
Oh and a note about the one achievement with the spam cannon attack. I deflected way over three cannonballs (three entire attacks) and then I got the achievement. So I think the description for that achievement is off. Or it's a glitch in the achievement itself.