World 6-4 (Super Mario Bros.: The Lost Levels)

World 6-4 is the fourth and final level of World 6 in Super Mario Bros.: The Lost Levels and the twenty-fourth level overall in said game.

Layout
Like with World 3-4, World 6-4 consists of puzzles where the player must choose the correct path in order to move forward. The player starts next to a small platform suspended over a pit of lava. After crossing the lava, the player will have to move through the correct paths ahead in order to progress through the level. In Super Mario All-Stars, if it is correct, a ding indicating so sounds; if wrong, a buzzer sounds. For the first path, the player has to jump over the pipe with a Piranha Plant and walk under the platform with a long Fire-Bar. Walking under the hanging pipe with a Piranha Plant, the player then needs to defeat or avoid a Hammer Brother and jump up the platforms to reach the top path, moving to the end and avoiding the Fire-Bars. Taking any other path will result in the player returning to the first pipe.

For the second puzzle, the player needs to take the lower path with the Piranha Plants, then jump across the platforms with Fire-Bars. Using the downward moving lifts if needed, the player needs to then take the next bottom path, avoiding the Podoboo and long Fire-Bar. Taking any other path will result in the player returning to the first pipe in this puzzle. After completing the puzzles, the player will have to avoid incoming Fire Breath as they jump across a large lava pit with a horizontally moving lift and jump over a pillar before reaching the fake Bowser. This fake Bowser throws hammers and also has a Podoboo jumping from below and a large brick formation above, within which is a Coin Block.