Press the squares starting with red, then green, then yellow, then blue and open the door. See related link for screenshots.
You go through all of the levels, doors, and adventures until you get to the very end, which is beating the final boss.
I believe that you beat the game again. You go to campaign and press new game. And you will unlock more doors if you beat it. I've been outside before on my uncle's 360. So try that.
You have to beat all of the levels and then you get extra levels when you beat it.
You lick me
In the game dooors by 58 works has 50 levels
Shake device
Its upside down
blow them up
Don't worry about it.
Beat all the levels!
You beat all the levels.
To completely beat the game, you have to unlock and beat all levels, get all the star coins in the levels, and beat Bowser's castle. Then, go to world 9 and beat all levels, including 9-9. To get 9-9, you have to get all star coins in the previous world 9 levels.