World 1-1 (Super Mario Bros. 3)
From the Super Mario Wiki
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The level begins with a Goomba walking towards the player. Continuing forward reveals a Fire Piranha Plant (a normal Piranha Plant in the GBA remake) lurking inside a pipe, along with more Goombas and Koopas. There are two ? Blocks in this area; one contains a Super Mushroom, and the other contains a Super Leaf. After this is a stretch of flat land, with two Goombas and a Red Paragoomba. The player will then encounter more platforms, some holding Koopa Troopas. They will also come across a stack of Brick Blocks; one of these blocks holds a P-Switch. Finally, they will then eventually reach the goal.
In the area of flat ground with the Goombas, the player can get a running start as Raccoon Mario and fly upward; this will take them to a secret area made up of clouds, with a ? Block containing a 1-Up Mushroom. Running and flying further past this area will take the player to a very tall pipe; inside is a bonus room with coins in the shape of a large 3. The pipe leading out of this room will take the player outside, right next to the goal.