Josh Thomas from the BitBlock is reporting that Super Mario 3D World will roughly take the average user around eight hours to finish the main storyline. Thomas also says that the game is fairly easy, which means that the majority of players will probably breeze through it. Super Mario 3D World launches on November 22nd in North America and November 29th in Europe.

http://mynintendonews.com/

Now I know he said this is his how long it took him to finish the game, but still. It sucks to know that I will be able to pretty much finish this mario in merely 2days. It also confirms that it is definetly not as long as both galaxy games which is also very disapointing. 

Did he complete everything? I completed Mario Galaxy story within 8 hours also. The extra levels/collectables were keeping me quite busy.

Change the title, everybody was arguing yesterday about it, its misleading. (saw this on neogaf)

The guy rushed through the game

So, two or three times longer than 3D Land?

the guy rushed through the game, meaning he didn't care for the star coins or the secret levels. just like LilChicken22 said, the story in Galaxy was also 8 hours long.

I beat the Super Mario 3D for the 3DS in four hours, but that doesn't mean anything. I had borrowed the game, meaning I had to rush through it. If I went to get all coins and extra-levels, trust me, the number increases!

I'll believe it when I see it.

Sure you can rush through it, but why would you even want to?

Other people on neogaf already said that it is far longer.

yeap, super mario games are short if you just go through it like an scared cat!

But remember Mario games are all about secrets

I got 3d land for 3ds a couple weeks ago and it may be my favorite 3d mario ever. It's an amazing cross between what makes the 2d and 3d games each good, and I beat it after about 10 hours (I've played almost another 10 hours so far trying to get through the secret worlds and I still have multiple star coins to collect). If 3d world is like 3d land, then the fun isn't just in the main story but in the bonus levels. Never had so much fun in bonus world mario worlds before.