Along with Foos and Paragoombas, the level contains Koopa Troopas and many Micro Goombas. There is a Propeller Mushroom in the level, found past the first Star Coin. A 1-Up Mushroom is also hidden three-quarters of the way through the level, and can be accessed by jumping on a Jump Block.
It is the only level to feature Foos, and is also the first of two levels to feature Paragoombas, the other being World 8-2.
Just ahead are some Micro Goombas. Get past them and climb up the Blocks to the ? Block at the top. It has a Fire Flower, so take it. Further along is a Foo. These weird looking creatures can breathe out massive clouds so that you can't see where you are going. Just jump on them to defeat them. Once past the first one you will just catch a glimpse of Star Coin #1 before a Foo blows a cloud in front of it. The platform is still there, so jump to the moving platform above and Spin Jump to move the cloud so you can find it.
There are some Bounce Blocks past the Foo which can be used to reach the Coins in the air. Hit the Brick Blocks and ? Blocks past here for another Propeller Mushroom. Spin Jump up the gap from the moving platform and grab the Coins. Drop down the other side and hit the Brick Block for a Fire Flower. Get it and then run into the thick cloud ahead. Spin Jump around the place until you find some Brick Blocks on the left side, one of which has a P-Switch. Hit the Switch and jump off the Bounce Blocks into the air to find all of the Blue Coins. Keep spinning so you can see where you are going, and to shake off any Micro Goombas that may have found you in the fog. Jump out the right side when you're finished.
Use fireballs to take out the Goombas constantly falling out of the pipe, as well as the Koopa and the Foo ahead. Jump to the Checkpoint Flag and then hit the top ? Block for a Fire Flower. Get past the next Foos to some Brick Blocks. Hit them for a P-Switch. Hit the Switch and shoot a fireball left across the new Birck Blocks to take out the Foo, then run across yourself to Star Coin #2. Make your way right, jumping on Foos and Koopas. Use the Bounce Blocks to get the Coins up above, then run past the Paragoomba and Micro Goombas to some Foos further up. Take out the first Foo and run through the wall behind it to a secret alcove with Star Coin #3. Climb the red ledges at the end and then bounce across the Bounce Blocks to the Finish Flag.
- Koopa Troopas
- Micro Goombas
- Star Coin 1: The first Star Coin is floating right above a platform near the beginning of the level, concealed by nearby Foos.
- Star Coin 2: A Propeller Mushroom can be used to get this one. Shortly after the first Star Coin, the second Star Coin, along with several other Coins, is floating under a platform with a Foo. Mario and co. must jump to it, then activate the Propeller Suit before falling. A P Switch is available in the bricks just to the right of the coin, which will allow Mario and co. to walk across.
- Star Coin 3: Shortly before the Flagpole, there are three Foos. Next to the lowest one is a hidden area which contains the third Star Coin.