World 4 is called Big Island. Here, you'll find out everything has become giant! This includes not just the terrain, but also the enemies, so take special care here.
You start off on a small part at the left which is connected to the island with pipes. The map contains multiple pipes which have been colored here, pipes with the same color connect together.
If you didn't use the Hammer from World 3 (or from World 2, for that matter), go through the pipe at the beginning and use the hammer to break the rock to the left. You then gain access to a special red mushroom house which contains a Tanooki Suit! The two normal mushroom houses here feature the standard mushroom, leaf, flower choice. There's another red mushroom house at the top left, it allows you to choose between a leaf, a flower and another Tanooki Suit.
This map has Sledge Bros. patrolling. They are similar to the normal Hammer Bros., but can stomp on the ground to stun you, so jump in the air to avoid this. They award a Jugem's Cloud, a P-Wing and a starman.
If you're Raccoon or Tanooki Mario, fly straight up at the beginning of this level to land in a water pool. Go down the first pipe you see to enter a bonus area (see below).
Since the enemies are giant here, you need to take your jumping height into account much more than before. That giant Goomba is not as easy to defeat as in 1-1.
Stomp on the giant Koopa Troopa, then kick its shell against the ? block to the right to get a raccoon leaf.
The waterfall behind the first pit provides another opportunity to get to the bonus area if you're good at tapping A. You still need Raccoon Mario to fly over the pipes that block the path, though.
The next giant ? block has another raccoon leaf.
At the cloud platforms, you can use the shell of the first giant Koopa Troopa to take out the second one. Stomp on the last of the three giant Koopa Troopas, then take its shell, jump onto the pipe and kick it to the Piranha Plant at the next pipe to take it out.
The pipe at the end takes you to the ending area, which is empty apart from the goal card.
Bonus area
You only need to watch out for the Big Berthas here. The brick blocks here contain coins and two 1-up mushrooms. Exit using the right pipe to return in the water pool.
4-2
The terrain here moves up and down just like in 3-3 and 3-8. No Boss Bass is here, but instead Cheep-Cheep jumping out of the water. This doesn't make the level much easier though.
Remember that for giant Piranha Plants, you can stand right on the edge of the pipe without taking damage.
When you see ice blocks, kick one of them down to the giant ? block to get a raccoon leaf.
You can in fact stand on the giant clouds - they are not just scenery. This may help a bit in the part with the Piranha Plants shooting fireballs at you.
After a while you'll come across a P-Switch which transforms the brick blocks into coins. Step onto it when the terrain is up.
The small ? block contains a starman, which helps a lot in the upcoming stretch where infinite Cheep-Cheep will be flying at you.
Collecting 24 coins (i. e. every single one) unlocks the White Mushroom House. This isn't exactly difficult to do, you just need to watch for those Cheep-Cheep.
4-3
This level starts off with two Sledge Bros. Since you do not need to fight them, it's best to just pass them and get into the pipe, which leads into the underground area.
The underground level is similar to the pyramid level from world 2. The difference is that instead of a maze, there are large pits here.
On the first platform, jump onto the blocks to avoid the Buzzy Beetle. Jump from up there to make it over to the other side. Watch out for the ceiling Buzzy Beetle there.
The lone block on the small platform contains a raccoon leaf.
You'll encounter a new enemy here, namely Spinies. These cannot be jumped on, so beware.
After the first Spiny, if you are Raccoon or Tanooki Mario, fly up to get to a secret path with some coins.
When you see the wooden blocks, get on them and then jump at the leftmost brick block for a 1-up mushroom. To get it, run to the right until the next set of brick blocks.
The pipe at the end takes you to the ending area, which just has the goal card.
Fortress 1
Part 1
At the beginning you'll encounter a new enemy: Hot Foot. These look like normal candles, but once you run past them, the flames walk off to chase you. They're rather similar to Boo Diddleys, in that regard. You'll see also Thwomps that don't fall down, but move horizontally.
At the beginning, just run forward past the candles, then drop down, the Thwomp can't catch you. Run to the next Thwomp, and once it moves, climb up the structure.
From the part where there are five pipes, you have two choices. You can either continue by sneaking through the Thwomps, this will lead you directly to Boom-Boom but is a bit risky. If you want the easy way, go down the middle pipe to get to part 2.
Part 2
Run down, jumping over the Dry Bones. The fifth block from the left has a Fire Flower.
The end looks like a dead end, but jump around to discover hidden blocks, which you can use to climb to the top. Watch for the Boo Diddley though which will chase you.
The pipe takes you back to part 1, but directly in front of Boom-Boom's lair. Stomp on him three times or feed him five fireballs to defeat him.
4-4
The first block you see contains a Fire Flower.
There's a bonus area in the lower left corner but normally, it is only accessible to Frog Mario due to a water current. A bug allows it to be accessed by any other Mario as well, though. Swim so you land on top of the ? block, then hold left and you should see Mario soar right through the water current, which allows you to enter the bonus area. (see below)
The Lakitu here will throw Spinies into the water. You may want to stay at the seabed to avoid them. However, there are no other enemies in this level, which makes it comparably easy.
The pipe at the end gets you to the ending area. Collect the goal card to end this level.
In Super Mario All-Stars, the water level has been changed to be consistent throughout the level. It's lower in the first part, but higher in the second part.
Bonus area
This bonus area has two secrets. First, swim up to the left cave. Jump at the single brick block here to uncover a P-Switch, step on it to make multiple coins appear in the room you're in.
After you're done with the silver coins, swim over to the right and hit the bottommost brick block. This reveals a second P-Switch. Collect some of the coins, then step on the P-Switch to transform the brick blocks at the top into coins, allowing you to collect them. Once you're done, take the pipe at the right, it takes you back to the level.
4-5
You will need a very precise jump to avoid the giant Green Para-Troopa jumping down the blocks. It is quite hard.
After the stairs, stomp on the giant Green Para-Troopa on the ground and kick its shell against the giant ? block to get a raccoon leaf.
Behind the pit, there's not just Bullet Bills, but also new Missile Bills which try to chase you. Since they can't move vertically they shouldn't be too much of an issue.
You can grab the Fire Flower if you want, but due to all the Bullet Bills, it may not be worth it.
After a small Piranha Plant, you should see a brick block above you. Jump to it to reveal a vine. To get to it, you must bounce off one of the nearby Missile Bills. Climb the vine to get to a bonus area (see below).
At the end, only jump down to go into the pipe if you're absolutely sure no Missile Bill will be following you. It leads into the ending area where you can grab the card.
Bonus area
The giant ? block contains a Tanooki Suit for you to collect. After that, jump on the P-Switch, then get out through the pipe to see multiple coins which you can use your newly gained Tanooki Suit to collect.
4-6
This level features an interesting concept. There are two "sides": a giant side (top map) and a normal side (bottom map). You start out on the giant side, but can go through the doors to get to the normal side, and vice versa. You'll want to get to the normal side as soon as possible, not just for the smaller enemies but also because the normal side has a few more goodies.
At the beginning, kick a Koopa shell against the brick block "cage" to allow you to get inside. You can then get a 1-up mushroom from the top-right brick block.
After the pit, jump over the pipe, get down (watch the Giant Goombas) and enter the door to appear on the normal side.
If you're Raccoon or Tanooki Mario, fly straight up from here to land on a cloud platform with another 1-up mushroom as well as some coins.
You can backtrack to the beginning to get a starman from one of the brick blocks if you really want. Another starman is hidden inside one of the wooden blocks to the right of the door, bump into them from the side.
In the area with a single Koopa Troopa between two Piranha Plants, there are some hidden blocks and a third 1-up mushroom at the right side.
When you run to the goal card, watch out for that last green Para-Troopa walking around there.
Fortress 2
Part 1
The first part has donut platforms that you must cross to get over a pit of lava. Since donut blocks fall down when you stand on them for too long, you cannot stand still.
The ? block at the beginning contains a Fire Flower. To deal with the Dry Bones, stomp on it to make it collapse, then stand on the donut block it's lying on and it will fall into the lava.
You'll see a dead end with a brick block. Jump at it to reveal a P-Switch, to reach it, you must jump off one of the Dry Bones.
The P-Switch will reveal some coins and a hidden door. If you just want to beat Boom-Boom, don't enter the door, instead continue forward to get to him. But if you want to get some rewards, by all means enter the door to get to part 2.
As for Boom-Boom, the blocks in his room make jumping a pain. Stomp on him three times or feed him five fireballs to defeat him.
Part 2
This is some sort of pipe maze. You start at the bottom and must make your way to the top.
Jump on the arrow block and it will move you upward. Jump off when you see wooden blocks to your right.
The lightbulb blocks behave differently. Jump on them once and they'll move upward. Jump on them again and they'll start moving to the left. Use this to safely get over the Piranha Plant and to the next arrow block.
Jump on the arrow block and stay at the left side to avoid the Piranha Plant. If you want to get a Fire Flower, take the right pipe, otherwise take the left one. If you got the Fire Flower, jump on top of the ? block, from there to the pipe and go down it.
The middle pipe will take you to the top. Jump on the lightbulb block twice so it moves to the left. When you see the gap overhead, jump again to make it move upward again and stay at the left to avoid the Piranha Plant. After having passed it, jump again and the block will move to the right this time. Once you see a gap again, jump to move it up. Enter the pipe there to get to part 3.
Part 3
You'll fall down into an area with a few coins. Jump around to discover some hidden blocks, which eventually lead to a 1-up mushroom. Once you're done, enter the pipe at the bottom to get to part 4.
Part 4
Jump at the giant ? block for three more 1-up mushrooms! If you're Raccoon or Tanooki Mario, you can also fly up the left side through the brick blocks to collect some coins at the top.
The pipe takes you back to part 1 near Boom-Boom.
Airship
After the cutscene where Mario discovers that the King has been transformed into a dinosaur, Mario jumps on the airship to fight the boss of this world.
This airship is filled with rocket engines which you must make your way around. As always, cross them when the flame is out.
If you're Tanooki Mario, this airship becomes super easy. Tanooki Mario can actually kill the rocket engines with his statue form, which removes most of the obstacles of this level. You just need to watch out for the single Rocky Wrench.
One block in the middle of the level contains a raccoon leaf. There's a second block at the very end of the airship, behind the pipe, with another leaf.
The pipe takes you to Iggy Koopa. As always, stomp on him three times or feed him 10 fireballs to defeat him, collect the wand to be taken to the next world. Princess Toadstool gives you a P-Wing for beating this world.
