On the stairs near the end of World 3-1, stomp on the second Koopa Troopa. Jump down to the next lower step. Leap and hit the left edge of the shell to knock it into the step.
There is a 1-up hidden above the right end of the bridge. In order to make the 1-up appear, you must kill the third goomba on the bridge, and leave the first two unharmed.
After the bridge, the block that's farthest to the left contains a star.
It's time to wage battle with the Hammer Brothers. If you proceed carefully, avoiding the flying hammers, you should be able to get past them.
The Springboard can be used to get the blocks above the pit, but there is a better way. Use to accelerate, and jump between the two sets of blocks. Punch the right block and find the beanstalk that leads to coin heaven B. Once the beanstalk is out, you can jump down to the left and use the Springboard to get to the beanstalk.
On the steps to the flag, an expert player has a chance for "infinite" 1-ups. If you catch a Koopa Trooper on the edge of a step, knock him into the back step over and over while keeping Mario above the next step down. This takes a few tries to master.
After the four "?" blocks, the block second from the left contains a 10-coin block. Be sure to cash in on it.
At this level, after you've stomped on the turtles, kick them and then chase them. With skill, you can destroy a lot of enemies, and you might even pick up an extra life!
You must deal with a lot of Troopas and Goombas here. The "Kick and Run" strategy is the best way to score. If you're good, you can go for the extra life bonus.
There is a star in the top block and a 10-coin block on the bottom. Since the Troopas on the ground are dangerous, it's better to get the star before you get the coins.
In this section and the next, the enemies appear in great numbers. But it's a great place to score a lot of points. Again, the "Kick and Run" strategy is your best bet.
Lifts are found throughout the Mushroom Kingdom, but they are most common in the tree top worlds. There are many different types of lifts: 1) Horizontal which move left and right; 2) Vertical which go up and down; 3) Elevator which continually move up or down; and 4) Balance which work like a see-saw--Mario jumps on one end and it goes down while the other end goes up. But beware, some lifts just drop down when Mario lands, so be prepared to move fast.
Wait for the Goombas to jump down to the lower island, and stomp on them.
The power-up is heavily guarded by the Troopas. Take your time, and try to power up without getting caught.
Mario's weight will make the last lift in this section sink. Jump to the island to the right as fast as you can, or you'll go down with the lift.
Watch out at the end of this section. Don't jump down to the lower island, because you can't get back up. Stay on the upper islands, and collect all the coins that you can.
Use maximum precision to clear the horizontal lifts. First, use one of the balance lifts to get to the lower horizontal lift and then hop to the small island. Once on the island, you can accelerate, and jump to the treasure island with the coins.
Defeat the flying Paratroopas before you attempt to cross to the right.
The balance lifts located just before the end makes it hard to jump to the top of the pole, but there is a way. Stay on the left lift until the lift on the right rises. Use to accelerate. Jump to the right lift, and then on to the top of the flag pole.
Single fire-bars are easy to handle once you get the hang of it, but double fire-bars are another story. The only way to clear this kind of hazard is to accelerate, and jump over it. The lower bar can be avoided easily if you time your jump correctly, so concentrate on the higher bar.
Poboboos shoot out of the multiple pits, so clear them with utmost caution. Time your jumps carefully, and cross the area when the fire-bars are pointing down.
A set of fire-bars rotate in different directions, starting at the end of this section. Needless to say, they are deadly. Stay to the left and watch for a while to learn their movement patterns. Then jump with care.
The pits are close together, and you'll be constantly bombarded with Bowser's fire breath. If things get too hot, seek refuge in the low spot to the right, just before the drawbridge.
Once again, blocks hang from the ceiling over you and Bowser, which makes jumping risky, but not as much as it was in World 2-4. Just hit the switch to finish him off.