World 4-2 (Super Mario Bros.: The Lost Levels)
From the Super Mario Wiki
The player starts facing five Bill Blasters with a ? Block containing a power-up between them. After the Bill Blasters is a Super Star within the Brick Block, followed by a Springboard after some gaps and Buzzy Beetles the player can use to reach a higher platform. On this platform, the player will encounter a Koopa Troopa and a Lakitu, the former of which the player can kick to defeat a row of enemies underneath. After a tall pipe with a Piranha Plant is a row of ? Blocks over some Bill Blasters, the left-most block contains a power-up and the right-most block contains a Poison Mushroom. After a Coin Block suspended over a pit is a Hammer Bro. before the path splits. At the end of the upper path is another Hammer Bro., and the first pipe at the end of the bottom path is a Warp Pipe to an underground area with Coins and Hidden Blocks containing a power-up and a Poison Mushroom. After the pipe at the end of both paths (which is the exit pipe from the underground area) are scattered platforms with a Koopa Paratroopa above them before the Goal Pole.