A guide to completing World 6-4 in Super Mario Bros 1 for the Nintendo Entertainment System.

How to Clear World 6-4

Go to the right and jump over the fire pit. Farther to the right, there is a fire bar, then a Podoboo jumping up and down out of a flame pit. Carefully jump onto the middle platform, which also has a fire bar, and you can optionally hit the ? block to get a Mushroom or Fire Flower. Then jump over the next Podoboo fire pit while avoiding the fire bar on the other side, and continue on while running, but you may need to slow down before the third fire bar to avoid hitting it.

There are five fire bars in the next area, two hanging from the ceiling and three on the ground.

Go right and you will have to dodge some of Bowser's breath. After you go down from a ledge, jump up and down as you go left and right, you should be able to find three hidden blocks. There are three more hidden blocks above the ones you revealed, but they are one square to the right of the revealed blocks. So get on top of each block you revealed, and jump up and slightly right to find the other three blocks.

Then go to the right and you find Bowser on the bridge. This Bowser throws a lot of hammers, and there is a Podoboo going up and down near the left side of the bridge. As before, you can hit Bowser with fireballs if you're Fire Mario , or run beneath Bowser when he jumps, or jump on the moving platform (but be careful of the hammers).

After you get past Bowser, you are once again told that the princess is in another castle. You will continue to World 7-1.