Super Mario Bros. 3/World 7 Part 3

7-9

 * This area is similar to 2-1, but structured as a giant maze. You have to find the correct passage to the exit pipe to finish this level. There are lots of dead ends here to mislead you.
 * Run forward and jump on the middle note block for a Fire Flower. Get all the way up (but watch the Para-Goomba), then go to the left through the ice blocks and jump to be on top of the structure.
 * Go to the right until you come across more note blocks. Drop down, go through the left wall of ice blocks and continue until you get to the wooden blocks, then drop down and go to the right (but watch the Para-Troopa). The middle ? block at the end contains a Fire Flower.
 * If you want to go for a 1-up mushroom (make sure that you still have enough time remaining before attempting this!), drop down after the Para-Troopa and follow the path to the left. You'll end up in a room with a row of coins, in the middle there's a hidden 1-up mushroom, duck and jump to get it.
 * Otherwise, jump up and continue to the right. Climb up the wooden blocks, continue to the right through the ice blocks, go down, and at the bottom go right again. Now, jump up then drop down behind it to finally find the exit pipe, which leads to the ending area. Collect the goal card to end this level.

Part 1

 * The idea here is to jump across all the pipes to get to the end. Of course, there are Piranha Plants and Boo Diddleys scattered all across this level to make this objective hard.
 * After the third pipe, you'll see brick blocks underneath. Drop down and carefully hit the first one (don't fall into the lava) to uncover a starman. Collecting it is necessary to get past the first Thwomp, so grab it and run forward. Hammer Mario can of course just throw hammers instead to take out that Thwomp, and Tanooki Mario can use his statue form, but it is still recommended to grab the starman.
 * Near the end, you'll see a ? block with a raccoon leaf inside. Afterwards, you'll see a second Thwomp. To get past it, jump carefully near it to trigger it falling down, and when it gets back up jump onto its pipe and right onto the next pipe.
 * The pipe to the next area is guarded by two Boo Diddleys, jump past them and look their way to avoid them. Carefully drop down onto the pipe and go down to arrive in part 2.

Part 2

 * At the beginning, you'll see a Roto-Disc and a small gap where you have to duck to get past. Don't run and duck, but go towards it to notice two Dry Bones behind it. Wait until they get to you them stomp them, afterwards you can pass the gap safely.
 * There's a Thwomp behind the next gap. You can either try to get a running slide to make it through the gap and the Thwomp in one go (rather difficult), or go near to cause the Thwomp to fall down and afterwards slide past the gap.
 * At the end you'll meet Boom-Boom as usual. Stomp on him three times, feed him five fireballs or lob a single hammer at him to defeat him.

Piranha Plant 2

 * Jump onto the horizontal pipe and do a running jump to get onto the first vertical pipe. From here, you can do one large jump to clear the first Muncher area. From here, run down (you can get past the Piranha Plant overhead without getting hurt), and jump onto the next pipe.
 * You will need to use the note blocks found here to get past the second Muncher area. If you fall down you'll more than likely get hit unless you have insane reflexes. At the end you'll have to bounce off a Para-Troopa to get to the end.
 * Go down the longest pipe to get to the ending area. Open the treasure chest to get a mushroom, this will end the level.

Airship

 * After the cutscene where Mario discovers that the King has been transformed into a Piranha Plant, Mario jumps on the airship to fight the boss of this world.
 * At the beginning, there's a nut. You could use it to cross the pit but there's two rocket engines in the way. It is a far better idea to simply jump from rocket engine to rocket engine.
 * After this part, drop down if you want for a Fire Flower. Afterwards, again either use the nut or just jump across.
 * The Rocky Wrenches can be a pain. There's a nut above your head that prevents you from jumping, so you'll need to evade the wrenches in some way. After that part you can jump up and go to the left for another Fire Flower.
 * In the next part, you need to jump from platform to platform, you can use the nuts but you don't need to. At the end is the only point where you actually need to use the nuts, to jump from the bottom to the top.
 * Enter the pipe at the end to fight the last Koopa Kid, Ludwig von Koopa. He can stomp the ground like Roy to stun you, and once you are stunned, you will be killed. Stomp on him three times or feed him ten fireballs to defeat him, then get the wand to be taken to the next world.
 * At the end, you'll be in for a surprise: Bowser has taken the princess and if you want to rescue her, you're going to need to get to his castle...