Super Mario Bros. 3/World 2

World 2 is called Desert Hill. As the name already says, the levels here are primarily desert-themed. Difficulty is starting to pick up slowly from this point.

There are two Boomerang Bros. in here. One awards a Music Box, the other awards a Hammer. There are also two Mushroom Houses in the left part where you have the choice, again, between a mushroom, flower and a raccoon leaf.

Using the hammer in the top right corner reveals a secret right part. Besides a Fire Bros. with a warp whistle, there is also another Mushroom House here which contains the Frog Suit, an item which will prove to be very helpful in the next World.

2-1

 * Right at the beginning you'll meet a new enemy, Pile Driver Micro-Goombas. They usually hide among brick blocks and look like one, but try to jump on you when you come near them. In the NES version, they can be easily distinguished from real blocks because they don't shine. You can easily take them out by jumping on them.
 * The first ? block contains a raccoon leaf.
 * After the brick walls, there are two ? blocks, the right one contains a starman.
 * Just before the violet structure you'll encounter another new enemy, Fire Snakes. They can only be killed by whacking them with Raccoon Mario's tail, so it's best to avoid them.
 * The brick block behind the first Fire Snake contains a leaf. Again, you can use the Koopa Troopa just a bit before to get it.
 * Once you're on the first violet structure, fly straight up to get to the bonus area 1 (see below)
 * You can enter the violet structures from the bottom right corner if you wish by breaking a brick block. The first violet structure contains a 1-up mushroom, the second one has many coins.
 * Between the two violet structures, the left wooden block contains another leaf (bump into it from the side). To get back up once you've fallen down, jump at the middle to discover a hidden note block.
 * At the end you'll see two pipes with Piranha Plants coming out of them. Go down the second pipe to arrive in bonus area 2 (see below).

Bonus area 1

 * This area is empty at first, but jump on the P-Switch to make 16 coins appear. Afterwards leave the area, you'll end up above the second violet structure.

Bonus area 2

 * This area just contains a single P-Switch. Step on it, then quickly get outside and all the brick blocks will be transformed into coins for you to collect.

2-2

 * You'll encounter quicksand at the beginning. It slows you down a lot and if you sink down completely, you die. Take a good running jump over quicksand fields to avoid them.
 * Bump into the first wooden block you see to get a raccoon tail.
 * After the quicksand, you'll come across a wooden platform that takes you through the second half of the level. If you fall down, you can swim back through the pool of water and the wooden platform will re-appear, but watch out for the Cheep-Cheep in the water.
 * You need good reflexes to bump into both brick blocks at the beginning if you're Super Mario. The left one contains a coin, the right one has a P-Switch which will transform the upcoming brick blocks into coins.
 * Between the groups of coins, you can find a hidden 1-up mushroom.
 * Collecting 30 coins in this level unlocks the White Mushroom House. This is very tricky because of the limited time you have until the coins become brick blocks again after activating the P-Switch, and the last group is located almost at the end of the level.
 * In Super Mario All-Stars, three coins were added at the beginning of the water pool. This makes getting the White Mushroom House much easier because it removes the requirement to collect any coins from the group at the very end.
 * The pipe at the end takes you to the ending area, which is empty apart from the goal card.

Part 1

 * You'll encounter a new enemy at the beginning, Thwomps. They fall to the ground when you come near them and then move back up. That's your moment to cross them.
 * Somewhat farther you'll encounter your second new enemy: Boo Diddley. Look into his face and he will be immobile, turn your back against him and he will move to you. You can't defeat them at the moment so be careful of them.
 * At the top part, watch out for the floor spikes. Do a careful jump over the spikes to not accidentally end up inside the Thwomp.
 * After this Thwomp, the single brick block you see contains a raccoon leaf. Run and duck to reach it as Super Mario.
 * From the brick block, you can just run across the room. You'll make it to the other side unharmed since the Thwomps don't fall fast enough. Go through the door to end up in part 2.

Part 2

 * The spikes move up and down. Wait until they get back up and then quickly cross the first two spike fields (or just one if you're not confident).
 * After these two blocks of spikes, you can either choose to continue as before, or try to jump over the spikes using the wooden blocks. This is very risky though because they are very small, and also because of the Boo Diddleys in this room.
 * After the fourth spike block, don't continue, this is where the door is. Enter it once it moves back up to get to part 3.

Part 3
Walk forward to meet Boom-Boom again. He doesn't behave any differently from how he did in World 1. Stomp him three times or feed him 5 fireballs to defeat him.

2-3

 * This level features pyramids made of orange blocks. These are not solid from the side, you can walk through them without any difficulty. You can also jump up to the block above you.
 * The first two pyramids have two ? blocks at the tip. Big Mario can access them easily, small Mario will have to use the Koopa shells. The right ones contain a raccoon leaf and a starman, respectively.
 * For the third pyramid, check out the left ? block for another raccoon leaf.
 * After this part, you'll see pyramids made of brick blocks. If you're not Raccoon Mario, feel free to kick the shells of the Koopa Troopas here down to destroy some of the brick blocks. One of the brick blocks in the pyramid hides a 1-up mushroom.
 * From the second pyramid, jump around to uncover hidden note blocks (check out the map). They lead to a platform with a few coins.
 * If you are Raccoon Mario, jump from the first note block to the left to uncover more hidden blocks. Climb all the way to the top, then soar to the left. The left brick block contains a P-Switch, step on it and then fall down to collect all the coins at the bottom (it's a lot!).
 * At the end you should see two Koopa Troopas in an enclosed structure of brick blocks. Stomp on one, kick its shell and jump out. The shell will destroy all the brick blocks allowing you to get to the pipe. When the shell is done, stomp on it to stop it, then jump at the single brick block remaining, it contains multiple coins.
 * If you're Raccoon Mario, wag your tail against the brick blocks at the very end for some more coins.

Quicksand

 * Present throughout this level is the Angry Sun. At the beginning it just hovers in the corner, but halfway through the level, it will start chasing you. You'll have to avoid it until you come across the goal card.
 * Expert players can use a Koopa shell to take out the Angry Sun. You can use the brick blocks on the ground to keep the Koopa shell bouncing back and forth.
 * The large quicksand pit at the beginning requires a very precise jump to not fall into it.
 * The tornado in this level just pushes you backward if you run into it. To pass it, you must jump beforehand so it will launch you way upward.

2-4
This level has 2 routes. The upper one can be gotten to with Raccoon Mario only. He must break bricks near the upper left to get there.

The first thing you will encounter in this level is a Para-Goomba. After that, there are two Troopas on stacks of unbreakable blocks, with a bottomless pit in between the two. In the middle of the pit, there is a "?" box. To get the power-up in the box, grab a shell, stand on it, and throw it to the left. The power-up (a mushroom/leaf) will appear right below your feet, ensuring that you get it.

This particular level is infested by Boomerang Brothers. The first one will appear directly after a "?" box located directly on the ground. Your best bet is to use the shell of the Red Troopa that appears earlier to dispatch the Boomerang Brother, then to use the shell of the Green Paratroopa that appears directly afterward to activate the "?" box for another mushroom/leaf.

After a couple more enemies, there will be a solid platform with a Venus Fire Trap in a pipe on top. There is also a "?" box directly to the left of the upper left corner of the platform. Small Mario will be able to stand safely under the "?" box without getting hit by fireballs; larger forms of him will need to jump.

At the end of the level, a Boomerang Brother appears in front of the Goal Panel. His position makes it hard to get a star, unless you can fireball him while running.

2-5
This level introduces Chain Chomps. Use a Troopa Shell to get a Vine in the middle of the game, and climbing it will take you to a secret room with bricks that can turn into coins with a P-switch.

Pyramid
This level starts by entering a door (you don't have the option of passing it.) It has walls of bricks that you must either use a Raccoon tail or a Buzzy shell.

To find your way, you must first smash the wall of bricks in the middle path. Then, after the Piranha Plan, go up and the left, then up and to the right. You will then spot a pipe that leads to a small coin room, with a 1-Up block just out of sight at the top of the screen. To get into the pipe, you must find the hidden coin block that will allow you to jump over the wall that guards it. Players of the original NES version (such as people who are playing the game on the Nintendo Wii) will be able to search for a discolored spot in the background that represents the blocks; players of later versions will have to jump around blindly to the right of the small wall.

If you do not choose to take the shortcut, you will encounter a hill with Buzzy Beetles making their way up. Be careful sliding down; there is a bottomless pit at the end. On the other side of the pit is an uninhabited pipe that will you will emerge from if you entered the coin room. Up another hill is a series of Buzzy Beetles, both on the floor and ceiling. Those on the ceiling will drop down and whirl towards you as soon as you get close. After the Buzzies, there is another wall of bricks you need to break. Get past one last Piranha Plant and you're home free.

At the end, just after exiting via a pipe (not below the cards unlike a few earlier levels,) there is a single Boomerang Brother.

Secret section
One of the Boomerang Brothers will give you a music box, which will put the other to sleep. The other, however, will give you a hammer, which you can use to get to the upper right corner and break a rock. After breaking the rock, you can get access to a Toad's House with a Frog Suit, as well as Fire Brothers, which will give you the third and final whistle!

Airship
The king has been transformed into a spider. This green airship has the same enemies as the previous one, plus Rocky Wrenches. At the end, enter the pipe and stomp on Morton Koopa 3 times or pelt him with fireballs and you'll get his wand and receive a message from the Princess and a Jugem Cloud.