Great game overall
This is a well made game with a great visual style and music. The story felt a bit anime cliche, been I didn't mind that at all, in these type of flash game, less is more.
There were some areas I had to nitpick, such as upgrades don't come often enough, it should happen at least every 2 or 3 stages so you hero can get progressively stronger instead of stashing for one huge upgrade. Ledge grabs collision detection can be better, there were lots of times where it'll look like I'll grab a ledge but instead did a wall jump and fell to my death. Also HTH was completely null by sword. Sword is superior in every way due to it's range, I wish there was something to differentiate them so it would be constructive to use one or the other instead of relying purely on the sword.
I think the difficulty overall was very nice, not too hard and not too easy. Good balance of platforming and action. I never really died due to enemy attacks, all were ledge falls or spikes which comes back to cliff collision detection. Puzzles were just right, they weren't difficult at all but took a little exploring and thinking to solve. Boss fights were entertaining, look stylish and made you felt like a badass so job well done. They weren't difficult but that's alright, I play these games to relax and not get stress.