Just before the year comes to an end, we managed to secure and preserve a prototype build of Super Mario World! Dated the 25th of October, 1990 – a whole ten months before the game would hit store shelves within North America, it’s no surprise that there are quite a few notable differences within the game’s dialogue and graphics, with even some additional debugging features being present.

Screenshot Screenshot Screenshot


  • The sign at Yoshi’s House has different shading and lettering.
  • Text box font is much slimmer than the retail version.
  • Numerous script differences.
  • Donut Plains 2, Donut Secret House, and “Funky” match the Japanese version.
  • Star Road stages lead to the various test stages.
  • Mario will not die upon the timer running out.
  • Various debugging features are enabled.
  • In the staff roll, Boo Buddies and Big Boo are referred to as Boo Diddly and Boo Jackson.
  • Font graphics from an early version of The Legend of Zelda: A Link to the Past can be found.

Screenshot Screenshot Screenshot

Debug Features

Being a localization prototype, many debugging options are available, making going through the game a breeze! You’ll instantly notice that Mario is able to walk to any point of the map without completing the previous stage. If this isn’t powerful enough, pressing both Start + Select whilst in a stage will cause it to become instantly completed instead of just exiting the stage.

Dying in a stage is also virtually impossible, as holding up on the control pad and pressing select will cycle through Mario’s various power-up states. Switching to the cape power-up and holding the L and A button will allow the player to fly as long as they want, with another press leading to complete control over Mario’s movement anywhere on the screen.

The last debug feature we were able to notice relates to the castle ending screens. Pressing both the L and R buttons during it will replay the scene, and pressing both L + R and up on the control pad will view the cutscene for the next castle.

Screenshot Screenshot Screenshot

ROM Information

----| File Data |--------------------------------------------------
System:             Nintendo - Super Nintendo Entertainment System        
File:               Super-Mario-World-USA-Prototype.sfc
BitSize:            4 Mbit
Size (Bytes):       524288
CRC32:              1A9DD5C8
MD5:                62A0803AE6E5DECED9046D0DB563590F
SHA1:               6899B80730135075C71F42A0082591D1343F0305
SHA256:             84F6EE7B264B55916E3083BD6951970FFD0BD27FB4DA23F58AF4AD2F639868B7
----| Detection Data |---------------------------------------------
ROM Type:           LoROM
Cartridge Type:     Normal
----| Header Data |------------------------------------------------
New Maker Code:      N/A
Serial:              N/A
SFX SRAM Size:      0x00
Title:              SUPER MARIOWORLD     
Map Type:           0x20 (SlowROM-200ns; LoROM-32KB Banks)
ROM Type:           0x02 (ROM + Save RAM)
ROM Size:           0x09 (4 Mbit; Ok)
SRAM Size:          0x01 (16 Kbit)
Country:            0x00 (Japan)
Old Maker Code:     0x01 (Nintendo)
Version:            0x00 (v1.0)
Inverse Checksum:   0xFFFF (Bad; 0x4A9E)
Checksum:           0x0000 (Bad; 0xB561)

Overview Video


Download Super Mario World (USA) (Prototype)