Gygax Day

Today would have been Gary Gygax's 80th birthday. That has led some folks to unofficially declare today "Gygax Day." In honor of that, and inspired by a recent post I saw on the Dragonsfoot forum musing about what people saw as the defining characteristics of AD&D, I got to thinking about what makes an adventure feel to me like it's "in the spirit of Gary Gygax" and came up with this little list. It's not exhaustive and neither is it exclusive - not everything Gary wrote has all of these elements, and many of them are also present in material written by others, but taken in combination, the more of these elements are present in an adventure, the more quintessentially "Gygaxian" it feels to me:

• The adventure doesn't exist in a self-contained vacuum, but is connected to a larger milieu. Opposed factions and organizations are important, both on the largest cosmic scale (the alignments are not just personality descriptors but cosmic "teams" - the gods (and demons and devils) are not abstract but real and actively, directly concerned in the affairs of mortals) but also on the more mundane scale via guilds (including those of thieves and assassins) and other organizations (the intertwined brotherhood of druids, rangers, and bards, knightly and monastic orders, etc.). The actions of the player characters need to consider and interact with all of these larger-scale factors, and will be influenced by them both positively (pledging loyalty and service in exchange for aid and support) and negatively (making long-term, recurring enemies). 
• The overall situation of the world is, effectively, a loose strategic stalemate but the forces of cosmic evil have a small but growing advantage and if everything continues on its current trajectory will eventually win and the mortal world will be destroyed. Thus the actions of the player characters are consequential - they are the ones who are tasked with ultimately turning that tide and making a difference, and no one else (no organization of non-player characters) is going to do it in their place. Tied in to this is the fact that as-written the adventures are always hard for the PCs. In terms of pure statistical analysis they are doomed and can't rely on the dice alone to see them through to success, so it becomes incumbent upon the players to do clever things and figure out ways to change the situation in order to overcome or circumvent the inexorable math. This is the key to "good play" in Gary's conception of the game - not just making the right moves, but figuring out new moves. 
• The characters (at least the significant ones) are cosmopolitan and sophisticated in their attitudes - not only are they comfortable among mixed races and cultures, they're also assumed to have at least some knowledge of how magic works and the nature of the multiverse. Travel to other worlds and planes is commonplace, and so is at least broad familiarity with modern-day earth (including references to "anachronistic" earth culture). The world is in "medieval drag" as far as technology and style of dress, but most attitudes (including patterns of speech) are much closer to contemporary society than to the actual historical medieval period.
• The adventure locations themselves exist in a "de facto" state that is not limited strictly to the context of the scenario in which it is presented. While most of Gary's adventures (especially those that were run as tournaments at conventions) start with a defined "mission" explaining why the player characters have come to this particular place and what they're trying to accomplish there, the description of the location itself doesn't depend on that and could be used in a totally different context, encountered by a group on a different mission or even no mission at all - it could be stumbled upon completely at random. This makes the adventures less linear and limited, more expandable, more rational (because the contents of the locations generally make sense within their context and don't exist solely for the purpose of being "an encounter" for a group of PCs), and imparts a sense of belonging as parts of a greater whole - these aren't just challenges being placed in front of the players but are "real" locations that exist within the fantasy world and would exist whether or not the players visited them.

I could go on and on, but I think the above is a pretty good encapsulation of what I have in mind when I think of "Gygaxian spirit," apart from the obvious surface-level details (his detailed descriptions of locations and treasures, his particular Thesaurus-driven vocabulary, his focus on present-tense action rather than irrelevant history and backstory, etc.).