I've had my Wii U for about 8 months now. Most of the games for it have been about average in my opinion. I thought Zombi U was interesting, but not groundbreaking, and New Super Mario Bros U was fun, but not amazing. Then, The year of 2013 turns everything around.
First, The Legend of Zelda: The Wind Waker gets remastered. I played a little of it for the Gamecube and thought it was fun, but it is so much more accessible in my opinion on the Wii U. I was sure that this was going to be the signature title for the Wii U. Then, Super Mario 3D World came out. All I can say is: BEST... WII U GAME... EVER!! Everything about the game was amazing: the multiplayer, the powerups, the secrets, etc.
I know that a lot of people have mixed opinions about the Wii U, mostly because it had a less than stellar launch, but 3D World changed everything. It is a game that cannot be missed, and a game that I enjoyed every second that I played it.
Essentially the title of the review says it all. The HD graphics are amazing. There is more than enough levels to drown the hours of your day with. The multi-player is the best I have seen on a Mario game so far (I personally didn't like the multi-player on the side scrolling games, such as New Super Mario Bros U). All in all, this game is not only worthy as a must rent, but it is a must buy for any WiiU owner.