I just finished playing your game!
I am impressed, dude! You created quite the amount of levels, and each one felt well designed. The amount of the difficulty grew at a steady rate, and the platforming felt real smooth.
Honestly, I think the next step for you is creating a few more objects and enemies and pump out levels. Maybe change the ninja's jump sprite to look more like a ninja and less like a Megaman. haha
You did a good job with this game! Keep up the good work!