This is really fun game. Each world is filled with different new challenges and well thought out game mechanics. Most of the game isn't very hard apart from a few of the bosses and moons that took me a couple of tries to complete. The game is simple to learn but hard to master (im not even close) for example when i finished the story line i had only 185 of the 800 total moons hidden throughout all of the worlds.
This game is absolutely worth it! I hope nintendo continues to add new content/worlds into the game!