What do the SLUS / SCES / SLES numbers mean?

[Gemini-Phoenix]

All PlayStation games have these codes on their spines, but what do they actually mean? are they a code given to a game when it is announced for development or something?

And what is the difference between SCES and SLES which PAL games seem to have on them?

And how come rereleases (Like the Grestest Hits / Platinum releses) have the same number's on them? Surely they should be classed as a separate release and should have a separate number?

[anagrama]

It's the part number, equivalent to the catalogue number on a record or CD, or the ISBN number on a book. Practically every videogame ever has one.

[Querjek]

Fun fact: With Nintendo games and systems, the first part of this code is usually the development name of the console--i.e.:
DS games say "NTR-(etc.)", as its name was "Nitro"
Gamecube games say "DOL-(etc.) because of the "Dolphin" name

[davidleeroth]

And what is the difference between SCES and SLES which PAL games seem to have on them??

SCES = Published by Sony Computer Entertainment Europe (with one or two exceptions it seems)
SCED = SCEE published demos
SLES = Third/second party published games
SLED = Third/second party published demos
PBPX = In some pack-in demos

[kevincure]

Yup, davidleeroth has got it. In the US, we have SLUS (third-party), SCUS (first-party) and the occasinal PBPX. The European numbers tend to be in order from earliest to latest release.

In the US, a game was given a SLUS, I'm told, when it was being readied to be sent to Sony for QA. Therefore, there are a bunch of gaps where games were given SLUS but not released (such as Superman). SLUS goes straight from SLUS-00001 (air Combat, I believe) to 157x (the last EA games). SCUS is a little different, because at various times, Sony was using the digit after the SLUS-9 to sort games by genre, but they then gave up on it. SLUS-8xxxxx are trade demos, SLUS-9xxxxx are public demos.