I liked the graphics and the animation. However there are some control problems. The jumps (which are the main part of the game) are quite hard to control. First, there seems to be a small delay between the time I press the key and the actual jump. Then, if you are too close to a wall, the ninja almost do not jump. When I play such a game, it is nice to keep the direction pressed, it gives more rhythm to the game. Here I had to stop, get back, jump, stop again... It is frustrating when you die because of that. I also think you have a problem with hitboxes. Sometimes, I had the feeling that the arrow just went through my head.
About music, it is fine. However, voices are annoying after some minutes because they speak too often and it is always the same thing.
Finally, the theme. There are multiple rooms. I know the background is the same, blablabla,... I think the theme is here to challenge us and force us to be creative. There are plenty of jumping ninja, you need to find a way to be special.
I hope it will help you for next time ;) You have plenty of good things inside.