These levels are made by "Ryan" (Nintendo Network ID: RyanL181095) on the Wii U:
These levels might appear in the 100 Mario Challenge and will show the amount of Global Players played each level. If you want to bookmark these levels, you can if you want.
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Super Mario Bros. : Worlds 1 & 5
Super Mario Bros. 3 : Worlds 2 & 6
Super Mario World : Worlds 3 & 7
New Super Mario Bros. U : Worlds 4 & 8