Island hopping is the theme of this watery World, and it will test your jumping ability. Don't go through the area too fast, or you may run into an enemy ambush.
- Drop down the first pipe that you encounter to discover the coin room shown to the right. A total of 78 coins can be had here. On top of that, there are two power-ups hidden in the room. Break blocks and use a Superball to get all of the coins.
- Don't miss the chance to grab a Star halfway through the level. While you're invincible, you can smash through all of your enemies without fear.
- Drop down the pipe to enter the coin room shown to the right. There are 20 coins in this room, but the question is how do you reach them. Reveal the hidden block on the right side of the room to create a platform to jump up and escape.
- There's a 1-Up Heart just before the end of the level. To collect it, you must be big. Break the first block on the bottom, then hit the block above it. As the Heart falls, jump to the platform where the coins are to collect it.
Meet the Mekabons — robots that lose their heads when Mario is around! This world isn't too difficult, although there are a couple of jumps you need to make while being harassed by enemies.
- The first pipe leads to another coin room, shown right, which holds 78 coins. In addition to the ones you can see, there are a few more coins tucked away inside one of the blocks. Pop them out before you leave.
- A secret pathway awaits you at the end of this section. But only small Mario can access it.
- To reach the lower passage of this section, you must use an invisible floor that sits just above the water. You must be small to fit into the passage. Although you'll be giving up the chance to collect an Invincibility Star, you'll collect more coins. Don't miss the power-up just before the pathway ends.
- It's difficult to reach the upper exit of this world. You'll have to quickly hop up the small dropping lifts to make it.
In this underwater area, you'll have to man the Marine Pop and blast your way through the defenders. The automatic scroll won't cause trouble unless you fail to blast blocks.
- Try blasting all of the blocks you encounter. You can liberate power-ups and Invincibility Stars from them.
- The Torions attack like torpedoes in groups of three. Blast them when they first appear.
- The large octopuses are called Gunions. After you shoot a Gunion, it will explode into deadly fragments, so be ready to dodge. You can also just go around the passive octopi.
- Create gaps in the block walls large enough for the Marine Pop to fit through. Hidden in some of the blocks are power-ups that can make the Marine Pop increase in size.
- The coins at the end of the world have your name on them! Dash forward and gather as many as you can, then go back and collect the ones you missed.
- There are a few more secrets hidden inside the blocks, including a 1-Up Heart.
- Defeat Dragonmasu. Watch the pattern of Dragonmasu's fire and Tamao's movement. The bottom of the screen is a safe place to be.