I’ve completed all of the 39 episodes and this unlocked five more. Now I have to finish these. I already finished one of them. Apart from the last level, the episode was quite easy. I’m hoping I’ll finish the rest of them today.

EDIT: I’ve completed the rest of the episodes, and now the game is officially finished (I got the credits). I’ve also unlocked everything in the unlockables list including the golden ninja. This is a great and challenging platformer that I recommend to everyone.