I guess I'm slow to pick up on these things.  I recently noticed that almost all the NES cartridges I have have a unique code printed on them, for example Super Mario Bros 3 is NES-UM-USA-1 and Mega Man 5 is NES-MZ-USA.  I noticed that my N64 games have this two, but their location and format seems more consistent, and the are accompanied by "NUS-006 (USA)".  At first I thought the later was the type of cartridge, but all of my games have it though some of them use different capacity cartridges.  I'm not finding these codes on Wii or Gamecube games, but perhaps I'm looking in the wrong places.

I'd just like to know a bit more about these codes.  I assume that they tell Nintendo what game and version of the game is inside that cartridge, but do they tell you anything else?  Are they 100% unique or can the same code be used on a different platform?  And why doesn't my copy of Metroid have a code?

i believe the code system was only used for cartridge-based games. i could be wrong though.

The codes are present on all Nintendo software, despite platform. N64 games start with NUS-, GameBoy games start with DMG-, GameBoy Advance games start with AGB-, Wii games start with REV-, and so on.

For disc-based games, such as Tales of Symphonia for the Cube, it's something like:

DL-DOL (DOL for Dolphin, development code name for the GameCube)-GQSE (title code)-0 <disc number, first disc is marked with 0> -USA (region)

so

DL-DOL-GQSE-0-USA for disc 1
DL-DOL-GQSE-1-USA for disc 2

http://www.mobygames.com/game/gamecube/tales-of-symphonia/cover-art/gameCoverId,...