World 2-2 (Super Mario Bros.)

World 2-2 is the second level of World 2 in Super Mario Bros. This is the first underwater level in the game, and in turn, the first underwater level of the series.

Layout
The player starts with their character walking into a Warp Pipe, which will take them to the underwater portion of the level.

In order to move around in the water, the player needs to press the jump button to propel themselves upward. The player can also walk along the waterbed, but their movement will be slowed. In the water are many Bloopers and Cheep Cheeps that swim around, with Bloopers moving toward the player and the Cheep Cheeps swimming across the screen. Both enemies can also move through platforms and walls. In three locations in the level are areas with strong currents that will pull the player downward, so the player needs to rapidly swim in order to escape; if the player goes too far down, they will lose a life. The Warp Pipe at the end of the stage will take the player to the Goal Pole, where a Piranha Plant can be found in the pipe the player exited from.

Super Mario Bros. Deluxe challenges
In Super Mario Bros. Deluxe, the player can collect five Red Coins, find a hidden Yoshi Egg, and get a medal based on their score. The Yoshi Egg is found in a Hidden Block at the end of the block structure above the second strong current, and the score to beat is 25000. The Red Coin locations are:
 * Right above where the player starts
 * On the second platform
 * On the platform after the first strong current
 * At the bottom of the third strong current
 * On the top-right platform before the exit pipe

Enemies

 * Bloopers
 * Cheep Cheeps
 * Piranha Plant

Level statistics

 * Power-ups: 0
 * 1-Up Mushrooms: 0
 * Secret areas: 0

Trivia

 * This level was recreated in Super Mario Advance 4: Super Mario Bros. 3.

Mondo 2-2 (Super Mario Bros.)