World 1-A (New Super Mario Bros. 2)

World 1-A is a secret level of World 1 from New Super Mario Bros. 2, and it's themed around Warp Pipes. It has many Koopa Troopas, Piranha Plants, and Flippers. In order to access this level, you have to buy it after completing World 1-4.

Star Coins

 * Star Coin 1: Not too far into the level, you'll see a Flipper blocked off by Brick Blocks. Ground Pound these Brick Blocks (Small Mario is unable to access this), and it'll reveal this Star Coin.
 * Star Coin 2: At the part where you go down through Warp Pipes while dodging Piranha Plants, this Star Coin will be in plain sight, though it will be blocked off by a Flipper. Move a little bit to the left, but not past the Flipper under you, to open the Flipper blocking off the Star Coin. Then grab the Star Coin.
 * Star Coin 3: Right before the Flagpole, hit a Hidden Question Block in between the Warp Pipe staircase and the floating Warp Pipes. Then go into the Warp Pipe to the left of the Hidden Question Block. This will lead you to a room with a Big Piranha Plant, a red Koopa Troopa, and the Star Coin. Use the red Koopa Troopa (or Fireballs) to kill the Big Piranha Plant, and reveal the way to the Star Coin.