New Super Mario Bros./World 2

World 2, like many of its counterparts in the Mario franchise, takes place in the desert. However, it features a variety of terrain, such as flat plains for facing Lakitu, a wide oasis and a completely airborne platform ride. There are more red Toad Houses than green Toad Houses, and all but one requires Star Coins to obtain. This is one of two worlds that can lead to two other worlds. Depending on how one defeats the world boss, the following world would either be World 3 or World 4.

Level summary

Level	Star Coins
World 2-1	In the air around the third Pokey. Time your jump to nab it while leaping over said Pokey. Over the quicksand section, below a Pokey on a moving platform. Grab the coin before the platform descends. On a platform over a bottomless pit. The nearby moving platforms can shift a Pokey on to the platform with the coin.
World 2-2	High in the sky, after the second set of platforms with red Koopas on them. Requires Lakitu's cloud. In a small valley. Ground Pound through some brick blocks to get to it. In a coin heaven section accessible via a yellow Warp Pipe high up in the sky, directly upward from two adjacent pipes. Requires Lakitu's cloud.
World 2-3	Near the beginning of the stage. Wall jump upward when you reach the first split path and you will get to the chamber that contains it. In the section with many flippers. Maneuver around the flippers to get to the coin. In the large room of the final section, go left and up the shaft, taking the right path when you come to a split path. Make a leap to the right to reach the coin.
World 2-A	Above the water a bit to the right after the first red Koopa. Suspended midair below a platform near the end. Drift to the coin slowly after jumping from a Spin Block. Right in your path when going down the path to the red flagpole.
World 2-4	In a small alcove above a green pipe with a Piranha Plant inside. Wall jump up to get it. After emerging from the underwater cavern, ignore the switch and run left to obtain it. Between the two layers of blocks the Hammer Bros. fight from.
World 2-Tower	In the alternate path with the N-shaped block structures. Keep wall jumping on the first structure, jump off at its peak then jump on to the top of the structure to reach the coin. At the bottom-right corner next to the last spinning wheel before the Warp Pipe. At the top-left corner of the room with the rotating blocks. Wall jump between the wall and the red Warp Pipe to hit a switch that makes platforms appear so that you can collect it.
World 2-5	This airborne coin is between two Blockhoppers. Jump off the top of one as it is jumping to get the boost that lets you reach it. Around the second Fire Snake, jump to the middle of the set of blocks to reveal a P-Switch. Use a Blockhopper to hop on the P-Switch, then run across the block platforms formed at the left to obtain the coin. At the Boomerang Bro., fall into the quicksand and jump to the area with a grey block to go through a secret path. Descend down the series of grey blocks to an underground cave. The Star Coin is at the center of this cave. Use the Blockhopper inside to reach it.
World 2-6	Openly hanging in midair, soon after the green pipe. Easily visible in the air near the top of the screen. There might be two Piranha Plants on the top platform when you approach it. Also in the air, near the end of the aerial section with multiple vertical moving platforms.
World 2-Castle	Can be seen near the end of the indoor section. Wall jump up and fall into the gap to get it. Watch out for the nearby Spiked Ball. Up on a ledge early in the outdoor area. Use a Bullet Bill to give you the height boost to reach it. In plain sight in the outdoor section, near a bunch of Spiked Balls. A Mini Mushroom is needed to collect it.

Secret exits

World 2-3

Back at the room that can be flooded, there is an opening in the ceiling. When the room is flooded, you can swim into the opening to reach another chamber with a bunch of coins you can collect. However, if you swim up fast enough, you can also see another switch, this time hanging from the ceiling. The switch is only visible when the first switch is still active, and pressing it will flood the room even further. This will let you swim up more to reach a hallway at the top. Exit the hallway to reach the red flagpole.

This alternate exit opens a path to World 2-A, which itself leads to some major shortcuts.

World 2-A

Above the green Warp Pipe that takes you out of the oasis is an alcove with the yellow Warp Pipe. After you jump up from the last Spin Block, drift right and attempt to land on the red Koopa Paratroopa, which will bounce you up to the yellow pipe. Go through it to reach a blocked-off section of the original flagpole area, where you can obtain the third Star Coin. Go down the red pipe to be taken to the red flagpole. Jump to the right of the two blocks to hit two more hidden blocks, which will help you jump to the top of the flagpole.

The secret exit leads to the World 2 Cannon instead. This cannon sends you to World 5. The extreme change in climate isn't the only big difference between the two worlds, and the increase in difficulty can be hard to overcome.

World 2-4

This exit requires you to be Mini Mario to reach, so the hassle might not be as worthwhile as the secret exit in World 2-3, since the shortcut you unlock isn't as far. If you happen to have a Mini Mushroom in reserve or want total completion of the game, descend to the underground lake. As Mini Mario, you can walk on the water and pass through a gap at the left edge of the lake. This will take you to a mini Warp Pipe that leads to the secret red flagpole.

The secret exit opens a long path around the main route of the world that lets you skip past a few levels straight to World 2-6. You will also unlock a red Toad House on the way.

World 2-Castle

Defeat Mummipokey as Mini Mario. Due to the reduced power of Mini Mario's jump, you need to use Ground Pounds instead to damage it. If you have a Mini Mushroom in reserve, you can enter the fight normally and damage Mummipokey a few times before using your Mini Mushroom and dealing the final hit. As long as you finish off Mummipokey while in mini form, you have succeeded.

Defeating Mummipokey unlocks World 4.