Super Mario Bros. 3/World 1

This is the Plains World. The levels are pretty straightforward and should not pose too much of a difficulty. Interestingly enough, you can beat 4 levels and make it to the final World right from the first World.

1-1
You will start the level with two sets of two item blocks and a Goomba in front of you. The top right one contains a mushroom. Proceed over the pipe and you will find a Koopa Troopa. Jump on it once, then kick it to the right to hit the block containing a leaf. Kill the next three Goombas. Now, there are two routes:

Route 1 (Raccoon Mario necessary)
If you are Racoon Mario, collect speed and fly where a trail of 4 coins lead you. You will find a platform of clouds with a block that contains a 1up mushroom. There are two pipes at the very end of the level. Collect speed on the platform of clouds and fly to the right. Land on the top of the top pipe to access a secret room with a big "3" spelled out in coins.

Route 2
Continue to the right and you'll see Koopa Paratroopas. If you're Raccoon Mario and you're really skilled with them, you can stomp on them several times without touching the ground and get 1-Ups.

Finishing this level with a coin number a multiple of 11 and the tens digit of the point count the same digit (for example, 0001120 points and 22 coins) with an even number of seconds on the clock unlocks the ghost coin ship.

1-2
Early in this level, there is a pipe with Goombas coming out of it. Raccoon Mario can touch 9 or more of them without touching the ground and get 1-ups. There is a 1-up on top of the pipe in the middle of the level that takes you to the secret room. To get it, jump up on the pipe. The secret 1-up block is above the pipe on the right side. Entering the pipe will take you to a coin room. After exiting the coin room, it will take you back a little, and now you can collect the coins without getting a P-switch. Near the end of the level is another pipe with Goombas coming out of it.

1-3
In the middle of the mass of blocks in the middle of the level is a secret pink music block that takes you to a coin heaven.

One of the warp whistles is obtained in this level. Near the end of the level there are 5 blocks with a white block in the center. Crouch on the block for about 4 seconds and you will go behind the level obstacles. Run behind the finishing screen to access a secret item mushroom. Take the only object in the room to get a warp whistle.

1-4
This is an auto-scrolling level where you have to get at least 44 coins to get a White Mushroom House. The screen will stop scrolling when you get to a pipe to enter. After entering the pipe, a Boomerang Brother will be on your left. Stomp on it, and then get to the Goal Panel. Note that it is hard to get a star in this level because of the short distance between the Pipe and the Goal Panel.

Fortress
This fortress has 2 new kinds of enemies, podoboos, which are fireballs coming out of lava, and Rotodiscs, which circle around, and which you're going to have to be careful passing. At the far right there is a door, an item box, and a boney turtle enemy. Knock out the turtle and run to the far right of the level. Maintaining your P-meter, run to the left.

Whistle route
One of the warp whistles is obtained in this level. To get this you have to have a flying leaf. If you have a full P-meter, take off and fly to the left of the wall and fly right until you start moving right. Go all the way to the right and enter a secret door to be transported to a room in the fortress with an chest. The chest contains the warp whistle. If you take this route, it will destroy the fortress, but it will not open the lock.

Regular route
Alternately, if you don't want the whistle, enter the door at the right of the wall and you'll be in a room with a spiked ceiling that will come down to crush you. Follow until the door at the end is reached, and enter it to see Boom Boom. Stomp on his head 3 times and the fortress will be destroyed and a lock will open.

1-5
This is an underground level. You begin by sliding down and killing 4 Buzzies. After a while, there is a pink block similar to that in 1-3.

1-6
Raccoon Mario can fly over and get coins just about halfway through the level.

Airship
This is the first Airship. It has Bullet Bills and Cannonballs. Follow it and enter the pipe at the end and kill Larry Koopa by stomping on him 3 times. You can also use fireballs to defeat him (as long as you don't get hit, of course). You will get his wand and change the king back, and receive a message from Princess Toadstool containing a P-wing.