I want to be ready, so thought you could all contribute to the syllabus. Which will hang off the taxonomy.
If the kingdom is adventure, the phylum might be graphic and text, then we would have the class etc. I don't know that you would get all 7 hierarchies but perhaps you would.
I don't think a biological classification system works well for games.
With biological classification, Kingdom is very high up -- plant vs animal vs fungi vs bacteria, etc. You don't naturally have combinations of plants and animals. For example, the zinnias in your garden don't cross with your cat.
Hybrids could only exist naturally at genus, species or occasionally family level.
But there are games like Quest for Glory where people disagree if they are adventure or RPG or a hybrid adventure/rpg. You don't get that with biological kingdoms.
Biological classification seems to be by DNA or RNA or other stuff you don't see. The closest analog with games would be the underlying code.
There are various ways you could classify adventure games, but they wouldn't be hierarchal.
Point and click vs keyboard vs gamepad
By puzzle type
Inventory based vs mechanical vs standalone (not sure what they're called -- puzzles in Shivers, Jewels of the Oracle, or Safecracker as opposed to puzzles in Myst/RHEM) vs conversation puzzles vs other puzzle types
None required vs QTE vs other action vs timed vs timing vs aiming ability
By ratio of exploration vs story vs puzzles
By environment / literary genre
Fantasy vs sci-fi vs steampunk vs post-apocalyptic vs detective story vs ghost story etc. including combinations (Are the Myst games fantasy or steampunk? The linking books seem magical, but much of the environment and machines suggest steampunk)
By length or divisions
A game that takes 15 or 20 hours to complete has a different "feel" as opposed to one that takes 1 or 2 hours. A game that is split into chapters or "episodes" may never come together as a single game, even after all episodes are released.
By delivery method
Hard copy with various game-related stuff in the box vs disc in case vs download. Not really a choice anymore unless you collect old games, though Telltale had an "extras" box you could get along with their Tales of Monkey Island game (inside you got a cloth map, a coaster, a pin, a coin, some sort of card, and the crippled game in a DVD case).