Huge pits are a common sight in the Mushroom Kingdom, and this is just one of the many that you can explore. Coins and blocks are plenty down here, but the cramped tunnels might feel claustrophobic. Savvy Mario veterans can probably spot a familiar secret that will open up an alternate path across the world.
The level starts as you fall down a tall chasm, crashing through the blocks at the bottom. To the right are some more blocks you can ground pound through, getting the coins underneath. A power-up block is located between the first two coin pits. At the third coin pit, you can ground pound all the way through to reach a hidden cache of coins, as well as two coin blocks, one that contains multiple coins. Use the spring to get back up. You can also get some extra coins if you go back to the left, while you can jump up the platforms to the right for a Star Coin.
Pairs of Goombas and some Koopa Troopas are up ahead. There's another power-up block before the n-shaped arrangement of blocks. Jump up these blocks and jump from here to the fifth ceiling block from the wall. This makes a 1-Up appear, which you can collect by breaking one of the other ceiling blocks to the right, or just by rushing to the right until there is a gap in the ceiling. After the second Koopa Troopa, you appear to come to a dead end for tall Mario. The only was forward seem to be to shrink back into default Mario and run through the small tunnel, but you can also break the blocks above the wall to bypass the tunnel. There's a Goomba on some brick blocks up ahead, and a power-up block as part of a two block combination located over a pit. After the pit is a Koopa and the second Star Coin. The top of most of the brick blocks here are coin blocks, but the thickest part of the roof of the structure can be ground pounded through, letting you get the Star Coin underneath. Alternatively, if you're small Mario, you can use the shell of the nearby Koopa to break the walls of this brick block structure.
After the second Star Coin is a long log bridge. This bridge acts like a seesaw, tilting to the left or to the right depending on your position on the bridge. Stay on the left to tilt it as far as possible, then run across it to reach a high set of blocks with a Goomba. There's a 10-coin block here that you can hit very quickly due to its short vertical distance, letting you get the full total of coins and a Super Mushroom. A bit to the right is the checkpoint flag. After that, you will come to a set of three pipes. There is a hidden block directly up from the left of the two blocks with coins between the first two pipes, but you can get some additional goodies by going down the first pipe. Watch out for the piranha plants though, as they can't be killed without a Fire Flower or some invincibility granting item.
Going down the first pipe leads deeper into the underground. There are a bunch of coins here, and the rightmost brick block forming the bridge of coins is actually a 10-coin block. However, that's not all there is to this area. Knock the red Koopa into its shell, then kick it at the blocks lining the ground. Let the shell break all the blocks to open up a secret pathway. If you're too big to go through the path, get a running start, then dive as you near the tunnel to slide partially into it. If you stop ducking, you will automatically be pushed through the tunnel, into the hidden right side of this area. Ignore the many Goombas walking around on the blocks and go straight to the right, where there is a lone power-up block. Hit it to make a Mega Mushroom pop out, letting you destroy all the blocks and the Goombas, netting you at least two 1-Ups. Go through the pipe after the Mega form ends to return to the main stage. There is a power-up block to the left of where you emerge so that you can turn back into Fire Mario.
There are some more power-up blocks up ahead, so you don't have to worry too much about getting hit. Jump up the hill and stomp on the green Koopa. Grab its shell and jump across the pipes, then release the shell at the two brick blocks. The shell should bump into the first, letting you get the power-up within. Continue to the right and jump up the arrangement of brick blocks. Jump from here to some coins then to a 3x2 rectangle of blocks. Bump into the third from the right ceiling block to reveal another power up. Past these blocks is the second seesaw bridge. After the bridge is a green Koopa and a platform with some coins. Jump over one last gap to get to the exit pipe, which takes you above ground. Jump up the staircase here to get to the flagpole.
- The first coin is easily noticeable. Use the bump on the ground a bit to the left to jump on to the roof, then jump to the alcove with the coin.
- In a small brick fortress. Ground pound the top of the structure or use the nearby Koopa's shell to break through.
- Below the alternate exit pipe. See the alternate exit section below to find out how to get to it.
Just like the warp zones in Super Mario Bros., you can bypass the normal exit pipe if you manage to jump on to the ceiling of the level. To accomplish this, you must tilt the second lever platform as far left as possible, then quickly run to the right and jump. You should reach the small space just above the ceiling. Just run right until you get to a slightly larger space with the third Star Coin and an exit pipe. Go through the pipe and jump to the red flagpole on the other side.
This secret exit opens up a nice shortcut that lets you skip the third level, and even has a red Toad House as a bonus!