OK — DON’T READ ON IF YOU DON’T WANT SPOILERS!
Likes for me include that it is pretty damn big and probably qualifies as a ‘megadungeon’ with factions and little stories going on, NPCs for the players to interact with and some interesting challenges that include lots of traps, rooms where players may have to fight their way across boiling tar pits, volcanoes, flooded areas, etc. Dislikes include that some of it (well, quite a bit of it) seems more than a little monotonous (room after room filled with 10 ogres, 20 troglodytes, etc., just sitting around waiting for adventurers to show up).
Information is some parts is a little sketchy, but I actually prefer too little info rather than too much simply because I don’t want to read long winded essays on the history of every stick of furniture nor do I need exact counts of how many dirty socks are in the footlocker of the bedroom of the bugbear chief on the 3rd level. Just give me the bare bones and I can flesh out the details if need be. If I were ever to use this thing at the table, I would like the shorter entries since I can scan them right there at the table and, in a moment, know what the players are up against without having to stop the game so I can review several paragraphs of dense text.
Interior art is from Thomas Baxa, Mark Nelson and Dave Simons; three artists I don’t know much about other than that they did a bit of work for TSR back in the 2e days. Most of the art looks like the art from the comic books I remember seeing as a kid from the late 1970s — sort of generic and wholesome-looking, which is a plus for me. The style of art makes me think that having Batman or Wonderwoman appear in the picture would not seem too out of place.
There is no ‘overriding’ story to the dungeon other than this: Long ago, Zagig the Wizard built a castle made of three towers where he collected his trophies, housed his guards and performed his experiments. Then he vanished and the castle began to fall apart. The dungeons beneath it are intact, however, and lots of adventurers go there. Some return with treasure; some never return at all. Of the castles/towers, little remains other than the ground floors.
The castle itself consists of three towers on mesa-like formations connected by bridges. Each ruined tower has it’s own basement, so technically I guess there are three ‘dungeons’ but they have a few inter-connections between them. The main tower is ‘Tower Zagig’ which is supposed to be the most dangerous. The left tower is ‘The Power Tower’ in which Zagig performed his many experiments. It’s front door is guarded by a group of elves. The right tower is ‘The Tower of War’ which is guarded by dwarves. If I remember correctly, the dwarves and elves demand visitors pay them a tribute for the privilege of using the doors to their respective towers.
Potentially, players can just go to the Ruins to bag XP and gold. There are also several factions (groups competing to control the dungeons, escaped slaves, a cabal of magic users who use a section of the dungeons for their experiments) that could be interacted with and the imaginative DM could figure out other quests and conflicts.
Sadly, I doubt I’ll ever get the chance to use ‘Ruins of Greyhawk.’ My days of running players through dungeoncrawls are probably long behind me; I don’t like playing online and players in my area seem to prefer a different style of game. Lack of interest from the local pool of players is probably also keeping my own Megadungeon, Mines of Khunmar, as something I will get to finishing “someday.”* And, really, who cares? What is in ‘Mines of Khunmar’ that is any better than anything else a halfway creative person with a lot of time of their hands can make?
* “someday,” with each passing real day, becomes more and more like “never.”