A guide to completing World 7-1 in Super Mario Bros 3 for the Nintendo Entertainment System.
How to Clear World 7-1
Go to the right and jump on the pipes, then go through the door in the wall just after the pipes.
Jump onto the pipe with the Red Koopa Troopa and stomp it. If you kick the shell, and it slides past the side of the screen, it will reappear on the other side. Hit the three ? Blocks if you wish, then jump onto the pipe platform on the right. Then go up the leftmost pipe.
Go to the left where there are two Piranha Plants going in and out of the pipes. The Piranha Plants don't stop coming out of the pipes when you're nearby, so you have to wait for the leftmost Piranha Plant to go back into its pipe, then jump up into the pipe above it (or just hit it with a fireball or your tail if you are Fire Mario or Raccoon/Tanooki Mario).
The three ? Blocks just contain coins. While standing on the pipe you came out of, make a running jump to the left, and start pushing toward the right as soon as you are going up past the ? Blocks. If you did it correctly, you will land on top of the ? Blocks. Walk to the right side and jump straight up to make a hidden block appear, and get the 1UP Mushroom that comes out of it.
Go down below and defeat or ignore the Red Koopa Troopa. Then go up the leftmost pipe. From there, jump up and to the right. You can stomp and kick the Red Koopa Troopa to hit the two ? Blocks next to it. The leftmost block contains a Super Mushroom or Super Leaf.
Jump on the Note Block to go up and to the right, where there are two ? Blocks that each contain one coin. To the right of those two blocks, there is a hidden block that contains a 1UP Mushroom. If it falls off to the right, fall to the right and you will end up on the left side of the screen, where you can land on the pipe and catch the 1UP Mushroom when it falls there.
Go back up to the blocks where you got the hidden 1UP Mushroom, and jump onto the platform above that. Jump on the Wood Block and jump up through the hole.
If you are Raccoon or Tanooki Mario, you can stomp the Red Koopa Troopa, then stand next to the hole in the middle of the platform, and run away from it to build up enough speed to fly. Fly up the left side and you can fly into the pipe that points down from the coin area. Collect the coins, then jump up through the pipe up above. From there, you can jump onto the upper set of Wood Blocks, then jump up through the pipe above that.
If you aren't Raccoon or Tanooki Mario, jump up the pipes on the right while dodging the Piranha Plants. Jump on the Note Blocks to reach the top of the pipe on the right when the Piranha Plant goes back into it. Then jump on the Note Block to reach the Wood Blocks above. Jump onto the upper set of Wood Blocks, then jump up through the pipe above that.
If you can't use fireballs, your tail, or other things to defeat the two Green Koopa Troopas, try jumping up the rightmost hole in the ceiling to stomp on one of the Koopa Troopas, then try to quickly pick up that shell and walk into the other Koopa Troopa with it to get rid of both of them.
Before you go to the left, watch out for the Red Paratroopa that comes down the second hole from the right. Go past it when it is out of the way, and jump onto the Wood Block ledge on the left. Jump up to the higher level from there. Wait for the Red Paratroopa to be at the highest point of its flight, and jump on it to go straight up and hit a hidden block that contains a 1UP Mushroom, but try to land on the upper level afterward instead of falling straight down, because if you get too far away from the 1UP Mushroom, it will disappear. Collect the coins in this area, then go up the pipe on the right.
Then go to the right and hit the Goal Block to complete the level.
After the Level
Go through the pipe to the right of the level you just cleared, and you will reach a new island. You can go through the pipe on the right to reach a Toad House, where you can get a Super Mushroom, a Fire Flower, or a Super Leaf.
Then go back the way you came. If you want to make the White Mushroom House appear, you need to equip the Frog Suit before you enter the next level. If you're ready, proceed to World 7-2.