World 6-4 (Super Mario Bros.)

World 6-4 is the fourth and final level of World 6 in Super Mario Bros. and the twenty-fourth level overall in said game, taking place in a castle.

Layout
This level's layout is similar to World 1-4's, though with additional Fire-Bars and Podoboos.

The player starts the level on an elevated area with stairs heading downwards, ending at a pit of lava. Afterward is a platform surrounded by Fire-Bars and Podoboos, and with a ? Block containing a power-up above it. After a corridor of Fire-Bars on the ceiling, there is a room with more Fire-Bars placed on both the ceiling and the floor. Next is a room containing several Hidden Blocks before the bridge with the fake Bowser, which has a Podoboo jumping up from below and a horizontally moving lift above. The fake Bowser also starts throwing hammers.

Super Mario Bros. Deluxe challenges
In Super Mario Bros. Deluxe, the player can collect five Red Coins, find a hidden Yoshi Egg, and get a medal based on their score. The Yoshi Egg is found in a Hidden Block directly to the right of the first Fire-Bar, and the score to beat is 12000. The Red Coin locations are:
 * Above the lava pit to the right of the ? Block
 * Above the end of the corridor of Fire-Bars
 * Next to the second Fire-Bar on the ceiling in the bigger room
 * Before the fake Bowser, at the end of the room with the Hidden Blocks
 * On the lift above the fake Bowser

Level map
Mondo 6-4 (Super Mario Bros.)