The ninth world of New Super Mario Bros. ULTIMATE takes place high in the sky. It features elements from the past worlds and each of its 10 levels are based on them. There are no checkpoints except for in the final level. Star World 1 is unlocked by getting all the Star Coins in Mushroom Lake, Star World 2 is unlocked by getting all the Star Coins in Dry Dry Desert, . . . Star World 9 is unlocked by getting all the Star Coins in the other Star World levels and Star Crown is unlocked by collecting every Star Coin in the game.
Star World 1
This level is based on Mushroom Lake. The player starts on a grassy hill above a rapid river. Mario must traverse the hills infested with difficult enemies and then enter a beachy area. The player must be careful not to be swept away by the water and then board a small sailboat that travels the water, which takes him to the flagpole on the other side.
Star World 2
Star World 3
Star World 4
Star World 5
Star World 6
Star World 7
Star World 8
Star World 9
This is a rainbow level that takes place high in the sky. It is relatively short. Comets rain down that can knock Mario aside. Mario starts by a wavy road that leads into a shower of comets, some being 1-ups. This leads into a really high section where Mario can fall easily and then a final section with rainbow Donut Lifts. A big message by the end says "THANK YOU BUT YOU STILL HAVE ONE MORE CHALLENGE!"
This is the final level in the game and it is very difficult. It is the only level with no Star Coins and is unlocked by collecting every Star Coin in the game, a number which is to be determined. It is designed to show the progress of Mario history until that game. The player starts out in an 8-bit world and plays Super Mario Bros's World 1-1, 4-3, and 8-4. After defeating Bowser, they are warped a few years later and must play through an altered version of the first airship in Super Mario Bros. 3, with more enemies. After that, they are taken to Super Mario World where they must play Yoshi's Island 2, to Super Mario 64, where they must defeat the Big Bob-omb, Super Mario Sunshine and do an F.L.U.D.D clean up, Super Mario Galaxy and fight Kamella, Super Mario Galaxy 2 and freeze the Twin Falls, Super Mario 3D Land and fight Boom Boom, New Super Mario Bros. ULTIMATE and get an ultimate thank you by making Toad Houses infinite, giving you a certificate, and by creating a golden statue of Mario in World 1. The credits roll after touching the flagpole (which is in World 1-1) and doing a special victory motion.
The level is very long, so there are many mini-flags that would mark the end of an individual section and allowing the player to do another level and coming back to that one.