This is an underground level, with many rotating circular platforms, much like the ones in World 1. The main enemies in this level are Spinies and Swoops.
Mario begins the level on a mountain, where a Warp Pipe can be found inside of a wall. Heading through the pipe leads to an underground area, where a Piranha Plant can be found on a rolling hill. Two ? Blocks can be found, along with Spinies walking on the ceiling. A Piranha Plant in a Warp Pipe is found, along with two more Spinies. A rolling hill with three ? Blocks above it can be found, with a Super Piranha Plant at the end. The midway point is found after a Spiny above a rolling hill. After the midway point, a few more Spinies can be found climbing on the ceiling, nearby a small gap that leads to the water. A Brick Block containing a 1-Up Mushroom can be found at the top of the gap. Goombas are then found, along with more Piranha Plants. Some Swoopers can be found one ceiling above two rolling hills. A Red Ring is then found, along with a Spiny climbing on some Brick Blocks. A rolling hill with a Piranha Plant is then found, along with two Sledge Bros. on platforms. A POW Block is found on a Brick Block. By entering a Warp Pipe behind the Sledge Bros., Mario arrives in a mountain area, where a Spiny and the Flagpole are found.
- Star Coin 1: Shortly before the Checkpoint Flag, Mario and co. must use a Spiny to break the Brick Block that is covering a hidden area, thus opening the path to the first Star Coin.
- Star Coin 2: An Ice Flower is required for this one. There are three Piranha Plants; one inside a Green Pipe and the other two surrounding it. Mario and co. must freeze the Piranha Plant in the Pipe while it is at its highest point, then use it to jump up and get the second Star Coin.
- Star Coin 3: The right of two spinning rock wheels contains a Pipe which, when entered, leads Mario and co. to an area with a P Switch and four Spinies. Hitting the P Switch turns the Brick Blocks into Coins, thus making the third Star Coin accessible.