A guide to completing World 4-3 in Super Mario Bros 1 for the Nintendo Entertainment System.
Get All the Coins
If you want to get a hidden 1UP in World 5-1, be sure to get all the coins in this level without dying! If you don't, the 1UP won't be there!
Explore World 4-3
Go right and jump onto the mushroom. To the right, there are two red Koopa Troopas going back and forth. Carefully jump onto their mushroom without going too far to the right, then jump left and get the three coins there, then go back to the right and get the coins on the Koopa Troopas' mushroom.
Make a running jump to the right to reach the tall mushroom on the right. Then carefully go fall off the right side to stomp the Paratroopa and the red Koopa down below, and get the coins there.
Jump up onto the mushroom on the right. The ?-mark block above contains a Mushroom or Flower.
Make a running jump onto the pulley platform, but be sure to jump off to the right as soon as you get the coin, to prevent the platform from falling off. Then jump on the pulley platform on the right to get the coin there, and get on whichever of the two moving platforms on the right you are closest to. If you aren't on the rightmost moving platform, jump onto it now. Then jump onto the mushroom with the coins on it, and jump from there to the higher mushroom with coins on it. Drop down from there to get the coin down below.
The mushroom to the right has a red Koopa Troopa walking back and forth, so carefully jump up onto the mushroom and go right. There are three pairs of pulley platforms up ahead. When you reach the second pair, make the right platform go up, then jump onto it, then as soon as you get the coin, run and jump onto the platform on the right to get the coin there. Then jump onto the right platform, and from there jump onto the mushroom on the right and get the five coins.
Those were all of the coins, and there aren't any enemies ahead, so just jump along the mushrooms, jump onto the moving platform, wait for it to go to the top, and make a running jump to the right to hit the goal pole and move on to World 4-4.