World 1-2

World 1-2 is the second level of the 1985 video game Super Mario Bros. for the Nintendo Entertainment System and is the first underground level in the game. The level was designed by Shigeru Miyamoto and Takashi Tezuka.^[1]

Following the open, outdoor setting of World 1-1, World 1-2 immerses the player in a dark, underground cave or sewer. The level's design builds upon the skills taught in the first level, but in a more confined space.^[2] The ceiling forces players to be more precise with their jumps to avoid hitting their head and falling into enemies or pits. The level is populated with Goombas, Koopas and Piranha Plants, which emerge from green pipes.^[3]

World 1-2 is most famous for containing the game's first Warp Zone. Near the end of the level, there are two rising platforms. By riding the second platform to the top of the screen, the player can jump onto the ceiling and walk over the normal exit pipe. This leads to a secret room with pipes that allow the player to "warp" directly to World 2, 3, or 4.^[4] The discovery of this secret became a legendary part of gaming culture in the 1980s.^[5] If the player exploits a glitch that maneuvers Mario through the bricks next to the Warp Zone and enters the pipe leading to World 4, instead of entering World 4, the player ends up in the Minus World.