9 Secret Video Game Areas You Weren't Meant To Find (Commenter's Edition)
1. Minus World - Super Mario
Lastly, one of the oldest boundary breaking secret levels in all of gaming - "Minus World", from the original Super Mario.
Mentioned by Nick Salerno, to access, you need to employ a very specific set of crouches and jumps while going through some pipes at the end of level 1-2. Literally, I'm talking pixel-precise placement. One pixel off and it won't happen.
If done correctly though, you'll appear underwater in what the game calls "World -1". Apparently it's supposed to be "World 36-1", but even that glitches out, so fans have lovingly referred to this as "Minus World" ever since.
Sadly there's not much to do, as besides the enemy and obstacle placement being the same as World 7-2, the glitch you invoked to get here de-spawns the pipe at the end, leaving you stuck forever.