World 9 (Jeansowaty Levels)

World 9 is the first and only world in Super Mario Bros. - Jeansowaty Levels: The Lost Levels. It's a very weird world featuring 3 water levels, one castle level and also a hidden water level accesible by 9-4.

World 9-1
9-1 starts out with a small room with stairs and a pipe. Getting inside will result in the player being teleported to an underwater level. At the beginning the player will see a Hammer Bro., and later on many Bill Blasters. Swimming forward will result into Red Cheep-Cheeps, White Cheep-Cheeps and Green Cheep-Cheeps swimming towards Mario. Later, the player will see a connection made out of pipes and water stone, a green Koopa Troopa underneath, and also the flagpole. This level was made out of all the bonus rooms in Super Mario Bros..