World 1-4 (New Super Mario Bros. Wii)
World 1-4 is the first underwater stage of New Super Mario Bros. Wii and the fifth overall level of World 1. This level introduces Cheep Cheeps, Deep-Cheeps, Eep Cheeps, and three other underwater enemies. It is unlocked by completing World 1- and its own completion unlocks World 1-5 and World 1-6, along with an Enemy Course and a Red Toad House. This is the first level to feature the underwater theme, which plays throughout the underwater sections.
At the level's start, there are two ? Blocks, two Goombas, and a Warp Pipe leading underwater. After descending, there are two Cheep Cheeps that can be frozen so Mario can get to a ? Block, which contains an Ice Flower. There are multiple pipes that shoot bubbles around the level that can push Mario into walls or enemies.
The next area also has Deep-Cheeps which must be frozen along with the Cheep Cheeps. There is also another ? Block with another Ice Flower. Past here, there is a Red Ring in a secret area on top of the stage which makes eight Red Coins visible for Mario to collect, along with the level's midway point.
In the next area the road is blocked by an Urchin which Mario must freeze to get through. There is also a Star Coin guarded by a Mega Cheep-Cheep that Mario must freeze. Continuing on, there is another Star Coin guarded by two pipes which generate a current that keeps the player from getting too close. The Star Coin can be collected if the player freezes a passing Cheep Cheep and stands at the top of it as it floats up, fighting the current. The final Star Coin is a short distance forward, where an Urchin must be frozen to block the current and allow the player to pass and collect the coin. In the next area there is a Spiny Cheep Cheep that follows Mario. After destroying the Cheep Cheep Mario can get a 1-Up at the bottom of the screen. There is also a Fire Flower and a Super Star in the nearby ? Blocks. Mario must then go through a red Warp Pipe. Many Cheep Cheeps populate the next area, but Mario can use the Super Star to destroy as many as possible. After escaping from two Spiny Cheep Cheeps, Mario can take a green Warp Pipe back to the surface. There is a Koopa Paratroopa that Mario can use to reach the top of the level's flagpole.
An Ice Flower is required for all three Star Coins.