There's one well-known secret world in the original 'Super Mario Bros.' called the 'Negative World.'
It's just one of many of the hidden levels contained in "Super Mario Bros." and it's perhaps the most widely known. You can reach it by performing an awkward backwards jump in the game's second level, 1-2, like so:
It's so-named because of the '-1' seen in the 'World' area of the screen:
The level itself is just a standard underwater level, though it's impossible to progress beyond it. Exiting the level results in a loop.
To access hundreds of other hidden levels in the original 'Super Mario Bros.' is far more complex. You need three items to pull it off. First you need an original 'Super Mario Bros.' cartridge:
And a copy of 'Tennis' for the original Nintendo Entertainment System:
And a top-loading Nintendo Entertainment System:
First things first, insert 'Super Mario Bros.' into the NES and start playing.
Like this guy, but with a top-loading NES instead of an original model.
At any point during the first level, 1-1, pull the cartridge out of the system while the system remains powered on. BEWARE: Yes, this might break your NES, and your game. So try this at your own risk.
Replace the 'Super Mario Bros.' cartridge with the 'Tennis' cartridge in your top-loading NES. Press the reset button. The menu screen should appear, like so:
Start a one-player game and get moving around.
After a minute or so, pluck the 'Tennis' cartridge from your NES and replace it with 'Super Mario Bros.' Hit the reset button.
When 'Super Mario Bros.' reloads, it will load into one of the hundreds of secret levels in the game. Just look at this:
Even crazier? Every time you do the trick, you get a different secret level:
If you can get your hands on a working Game Genie — a device for hacking "cheats" into games —there's an even easier way to just input a code and access all these levels.
And for more information on the hundreds of secret levels in 'Super Mario Bros.," check out this episode of 'Pop Fiction' from GameTrailers.com!
