Ray said:
Conan isn't d20, its OGL. This means that Conan uses the basic game mechanics defined in the SRD, but it is not constrained to using the fluff, classes, races, etc.
Just a clarification of d20 vs OGL (based on my understanding of it):
1. You can publish your stuff as either compliant with the OGL or the d20 license.
2. You can use the material in the SRD for both types of publication (d20, OGL).
3. If you publish under the d20 license:
a) You may use the d20 system logo, which is good for marketing since gamers recognize this as compatible with their favorite RPG (D&D).
b) You must include a text saying "Requires the Players Handbook from Wizards of the Coast" (or a variant of this text) on the cover.
c) You cannot include rules for gaining XP and levels (this is, at least in theory, why the PHB is "required").
d) Your product must comply with certain "decency standards" as set by Wizards of the Coast (ie. no bare nipples, no condonement of drug use, racism, slavery, etc.)
4. If you publish under the OGL:
a) You can create a stand-alone game that includes the complete mechanics, including XP and level gain.
b) You cannot use the d20 system logo, which might be bad for marketing since potential buyers won't necessarily recognize this as a product compatible with D&D and d20 (although, since you are free to modify or make up new game mechanics, your game isn't necessarily compatible with D&D or d20 anyway -- but note that you are free to modify the rules when using the d20 license as well).
c) Your product does not, as far as I know, need to comply with the "decency standards" mentioned above. That's why the Conan RPG can have a bare nipple on every even-numbered page
Ray said:
A quick read of the Conan game aptly demonstrates the difference between Conan, OGL, and d20.
Since the Conan RPG by Mongoose is published under the OGL, there is no "difference" between Conan and the OGL. Perhaps a better way to say it would be:
"A quick read of the Conan game aptly demonstrates the difference between the Conan RPG (which is OGL) and d20."
- thulsa