Overall I liked it
I love the art work. I have to say that this was beautifully done. Very fluid and visually impressive. Now I didn't like the drawn combat system. It seemed that when I tried to do a normal attack I would be dashing halfway across the screen. The enemies were fun to fight but I wish that you had more than five different types (I'm including the final boss and the oni's). It was kinda short with only three levels but I think that the spacing was good and provided a nice pause in combat. The upgrade system was ok and took multipul play throughs to max it out.
Overall it is a very good game that will occupy about 2-3min. The gameplay, while challenging, is fun, and to unlock all the most powerful attacks you will need to play through a few times.
If you were to update this I would suggest adding more levels, make the final boss harder, and add an optional play style that used the keyboard.