A guide to completing World 2-4 in Super Mario Bros 1 for the Nintendo Entertainment System.

Explore World 2-4

Go to the right and you will see a fireball, a.k.a. a Podoboo, jumping up and down out of the flames. Jump over the gap after the Podoboo is moving downward, and get on the middle platform, where you can hit the ?-mark block to get a Mushroom or Fire Flower. Then go to the right and avoid the second Podoboo to reach the right side.

There are two paths you can take here, but it's best to take the lower path and hold the B button as you go to the right, because there are several fire bars along the path, and if you use the lower path, you'll run past them safely. If you use the upper path instead, you'll have to wait for each fire bar to get out of the way before you can continue.

After that, there is a fire bar just before a pair of poles with moving platforms on them. Carefully jump across the moving platforms, but watch out for the flame that shoots across the screen from the right, and the fire bar on the other side.

Next, if you're regular size, you can run under the block to get the lower coins, or if you're tall, you can run and crouch to slide under the block to get the coins. Then get the coins above the block and continue to the right.

Jump over the pits of fire while dodging the flames from Bowser.

To the right, you find Bowser himself, and this time there are some bricks over the left side of the bridge, giving you less space to try to jump onto the platform above Bowser. Of course, if you're Fire Mario, you can just shoot fireballs at Bowser until he's defeated. Either way, go to the right and you find another Mushroom Retainer who tells you that their Princess is in another castle. Then you continue on to World 3-1.