World 4-2 is the second level of World 4 in New Super Mario Bros.. It is a sky level, and it contains purple Mushroom Platforms that tilt based on which end Mario is standing on.
The level begins with a group of stationary Mushroom Platforms, where a green Koopa Paratroopa and a ? Block containing a power-up are located. A group of purple, tilting Mushroom Platforms above a pit follow, where Goombas and a Koopa Troopa are found. A section with a rock formation above two tilting Mushroom Platforms, and a Goomba can be found on top of some blocks, one of which contains a 1-Up Mushroom. The midway point is after the rock formation, along with a ? Block containing a power-up. Another section containing tilting Mushroom Platforms, Koopa Troopas, and Koopa Paratroopas follows, as well as a Red Ring. A section of ground follows, with an alcove where coins and a Brick Block containing a Beanstalk that leads to a secret are found. A third section of tilting Mushroom Platforms follows, where there is a section under another rock platform, followed by the pole.
- Star Coin 1 - The first Star Coin is located before the midway point, where it can be collected by wall jumping off the rock platform above.
- Star Coin 2 - The second Star Coin is found under a tilting Mushroom Platform with a Koopa Troopa on it after the midway point, where it can be obtained by tilting the Mushroom Platform above it or by throwing a shell at it.
- Star Coin 3 - The ground platform after the second section of tilting Mushroom PLatforms contains an alcove that can be reached by jumping off a Mushroom Platform next to it. There is a Brick Block containing a Beanstalk that leads to a secret area, where the third Star Coin is located and can be obtained by using another Beanstalk.