I am very disappointed that there is no viral content.
I can find nothing in the GSL which specifically limits GSL products to "fantasy". Would I be in violation if I created a "Gunslinger" class and added gunpowder weapons?
Section three says:
"Licensed Products. The license granted in Section 4 is for use solely in connection with Licensee’s publication, distribution, and sale of roleplaying games and roleplaying game supplements that contain the Licensed Materials and are published in a hardcover or soft-cover printed book format or in a single-download electronic book format (such as .pdf), and accessory products to the foregoing roleplaying games and roleplaying game supplements that are not otherwise listed as excluded in Section 5.5 (“Licensed Products”)."
Section 5.5 says:
"5.5 Licensed Products. This License applies solely to Licensed Products as defined in Section 3 and to the specified uses set forth in Section 4. For the avoidance of doubt, and by way of example only, no Licensed Product will (a) include web sites, interactive products, miniatures, or character creators; (b) describe a process for creating a character or applying the effects of experience to a character; (c) use the terms “Core Rules” or “Core Rulebook” or variations thereof on its cover or title, in self-reference or in advertising or marketing thereof; (d) refer to any artwork, imagery or other depiction contained in a Core Rulebook; (e) reprint any material contained in a Core Rulebook except as explicitly provided in Section 4; or (f) be incorporated into another product that is"
Nothing here seems to rule out modern, superhero, horror, or science fiction games, provided one is willing to make all new classes and races, create new feats, etc.
Can you ignore aspects of the templates -- for example, create a race which gains a bonus to no, or to 3, ability scores?
No specific demons or devils are listed; is this intentional? So no one can include a pit fiend or a succubus in an adventure?