There is a 1-up hidden above the right end of the bridge. In order to make the 1-up appear, you must collect every coin in World 2-3, or use a warp zone to reach World 3-1.
After the bridge, the block that's farthest to the left contains a star.
In Vs. Super Mario Bros., a Koopa Paratroopa is added along with that green Paratroopa which is changed to red.
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. It is easier if you collected the star a moment ago.
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.
In Vs. Super Mario Bros., be careful when reaching the springboard. It is between two pitfalls and on one block, so it is very difficult to use the springboard to get in between the two sets of blocks. Unfortunately, the beanstalk is a better way in this version of the game. Finally, the top platform with the powerup is all "?" blocks.
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.
In Vs. Super Mario Bros., the 10 coin block is omitted. Followed by an extra pit and the pit near the steps is longer. Also the infinite 1-up trick is omitted as the Paratroopa are replaced by goombas. Finally, the powerup is now on the top right row, which is now all ? blocks as well as all the other rows.
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. Stay for a moment next to the pitfall till the star effect ends, then don't miss the first Troopa to meet after the next pitfall and use the "Kick and Run" strategy to get a 1-up out of the killed enemies. You will be able to listen to the sound of the 1-up after killing all the 9 Troopas.
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.
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.
In Vs. Super Mario Bros., the lowest island directly before the last treetop with the two red koopas are omitted.
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.
In Vs. Super Mario Bros., before you get to the Power-up look out for 2 extra lava pits and a firebar on top of the ceiling in between the 2 lava pits.
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.
In Vs. Super Mario Bros., to make it even more difficult, there is one block of a lava pit on each side of each set of fire-bars.
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.
In Vs. Super Mario Bros., there is a Troopa after the first Podoboo and another after the last Podoboo.
In Vs. Super Mario Bros., there is a pit fall to the right of the low spot, just before you reach Bowser. Also after that pitfall two out of the next four blocks have a gap so you'll need to run through that.
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 axe to finish him off.