World 8-4 (Super Mario Bros.: The Lost Levels)

World 8-4 is the fourth and final level of World 8 in Super Mario Bros.: The Lost Levels as well as the thirty-second and final level in the game overall, taking place in Bowser's Castle. In the Super Mario All-Stars version of the game, there is lightning flashing outside the castle and on the level card, a trait this level shares with World D-4.

Upon defeating Bowser, the level progression changes depending on the version of the game being played. If no Warp Zones were taken, the player will progress to World 9. Beating the game eight consecutive times and holding down the A Button in the original game or the B Button in the Famicom Mini version for the Game Boy Advance will allow the player access to World A. In Super Mario All-Stars, the player only needs to beat Bowser once to access World A, though if the no Warp Zones requirement is met, the player will move on to World 9 instead. In Super Mario Bros. Deluxe, the game ends.

Layout
The player starts on some stairs. In order to jump across the pool of lava, the player has to fall onto the floor below and do a running jump. Then the player has to pass through a hall with Fire Bars on the ceiling, then run and jump across the next pool of lava, using the block on the ground as a step and avoiding the Hidden Block with a Poison Mushroom, the Lava Bubble jumping up, and the Fire Bar on the other end. Then the player has to jump off of a Koopa Paratroopa to reach the first Warp Pipe with a Piranha Plant, which leads to the next area. If the player continues jumping across the pipes in this room, it will loop around to the hall with the Fire Bars.

The next room is underwater, with Bloopers and Fire Bars. Simply entering the Warp Pipe on the other end will take the player to the next area.

In the next room, the player can find a power-up in a Hidden Block against the wall to the left. To enter the next area, the player has to jump onto the platform on the right and jump around it to land on the Warp Pipe below, avoiding the Piranha Plants.

The next room has three Piranha Plants, two Koopa Paratroopas, and a Blooper. A Poison Mushroom can also be found in one of the ? Blocks as well as in a Hidden Block after the second pipe. Going down the third Warp Pipe will take the player back to the underwater room. To progress, the player needs to take the lower path of stone platforms. The player must dash, not jump, over the small gap. (If the player takes the wrong path or jumps over the gap, the room will loop around back to the beginning.) The player must avoid the long Fire Bar as they jump up to the platform. After going through a long hall, the player then has to jump off of the Koopa Paratroopas to reach the Warp Pipe to the next area, which has a hidden power-up directly above it.

In the final area, the second Warp Pipe will lead the player back to the beginning of the level, and Hidden Blocks prevent the player from jumping out of the pit the pipe is in. After the pipes is Bowser's Brother, who will breathe fire and throw Hammers. After a long hall with a falling platform, a hanging Piranha Plant, and a Buzzy Beetle, the player will encounter Bowser, who also breathes fire and throws hammers, as well as having a Fire Bar above him. Defeating Bowser and/or touching the axe will allow the player to enter the chamber with Princess Peach.