World 6-4 is the fourth regular level in World 6 in New Super Mario Bros. 2. It is one of the only levels in the game taking place in a haunted forest, without being a Ghost House, the other level being World Star-3. It is similar to World 8-1 from the original New Super Mario Bros. game. This level focuses on Peepas, which move platforms by shaking them.
Mario begins the level near two ? Blocks, one of which contains a power-up. A Peepa carrying a lift vertically is then found, followed by a Peepa moving diagonally and a Peepa below a ? Block. A Crowber, two Boos, and more Peepas are then found. The Checkpoint Flag is then found, with two ? Blocks nearby. A lift that is carried by a Peepa when Mario touches it is found, below a ? Block with a Hidden Block containing a 1-Up Mushroom found above it. A Boo and a group of three Peepas holding lifts are found with a Red Ring. After a few platforms, another lift that Mario must ride on is found. Crowbers and a circle of Peepas are encountered while Mario rides the lift. Two more lifts are found, both leading to the Goal Pole.
- Star Coin 1: As soon the level starts, the player must head left to get the first Star Coin.
- Star Coin 2: Once Mario or Luigi see the first spinning Brick Block, they must jump on top to reveal a hidden block with a Vine. They must climb it, then time their jumps over the stone blocks correctly to get the second Star Coin.
- Star Coin 3: The third Star Coin is being circled by Peepas towards the end of the level. The player must wall kick to get the Star Coin.