Could be better

There is no sound or any thing that the player can appreciate, the down key was totally useless the last part: the spinning circles your on don't do anything that affects your speed. The game is ok but could use some editing.

Eh...

half and half
way too short

It has potential

It may have potential but it seems far from done.
There is no music or sound.
The graphics are decent I like the style bur is to empty besides the moon there is no real background, besides that the background objects seem out of place assuming you are running over the roof of some sort of factory the trees don't seem to belong there.
But the biggest flaw for me was the you lose screen whenever you fell down a tiny pit, you are supposed to be a ninja shouldn't you be easily able to climb out?

I also have a suggestion to make this game more fun and challenging by adding guards.
When I walked past a tree I noticed that the ninja is the exact same color as the tree, if you were able to close your eyes you would be completely invisible this way you could avoid guards and to make it even more challenging you could make the screen black out whenever you use this so you have to use timing or sound to know when a guard has passed you.

A decent effort.

It's very short, simple, and unoriginal, though the graphics and animation are pretty good in comparison to everything else. I would recommend adding more obstacles, especially something creative that platformers don't often have, and making it much longer. It barely took me twenty seconds to complete. You want to keep players busy for at least a few minutes. Overall, this is a mediocre game, but it has potential.