Worst. Module. Ever.
I try very hard not to be hyperbolic on this blog; I know I often don't succeed. But I am hard pressed to think of any module published under the Dungeons & Dragons banner that was worse than 1988's Castle Greyhawk. Consider: Gary Gygax's legendary Castle Greyhawk had never seen publication except in snippets (such as Dungeonland, Land Beyond the Magic Mirror, and Isle of the Ape). There were occasional -- unrealized -- intimations by Gary that TSR might one day published this megadungeon in a more complete form. When module WG7 was released, as part of the World of Greyhawk brand, no less, I am sure many expected it to be the fulfillment of a long-held dream. I know I did.
Unfortunately, Castle Greyhawk is more nightmare than dream -- a puerile, unfunny collection of shlock. "The common theme of this dungeon is that no joke is so old, no pun is so bad, and no schtick is so obvious that it can’t be used to confuse and trip up PCs!" That sums it up pretty well in my opinion and, if it hadn't been for the fact that the module was released in the wake of Gygax's ouster from TSR -- an event that shook the industry and the hobby -- I probably wouldn't regard this module with such bile. As it is, the entire thing comes off as a sophomoric attempt to belittle one of the co-creator's of the game and to destroy the game world he created for it.
Now, I'm not sure that it was in fact such a thing. Given that its twelve levels were written by a variety of freelancers, some of them extremely talented and well regarded (Paul Jaquays and Steve Perrin being stand-outs), it's quite possible that the whole thing wasn't so much a concerted attack on Gygax as a project that got out of control and took on a ridiculous life of its own. On the other hand, as many on this blog can attest, the late 80s were a time when many at TSR did make a real effort to besmirch Gary's reputation (This is when the ludicrous "Gary was a cokehead" rumor was started, after all). Likewise, Castle Greyhawk's ham-handed use of puns and pop cultural references (to Star Trek, for example) could quite plausibly be interpreted as pointed at Gygax, who both enjoyed humor and often included allusions and outright borrowings from pop culture in his home campaign.
My own sympathies lie with those who see WG7 as anti-Gygax, but I can't be certain there's any truth to it. Another possibility might have been that, while its origin wasn't defamation, the fact that it could be read that way tickled some of the higher ups at TSR, knowing they could hide behind plausible deniability should anyone confront them on the matter. Interestingly, this module's implicit criticism of Gary lives on at the Wizards of the Coast website, where an article by John Rateliff blames Gygax himself for laying the groundwork for this terrible module: "the parody element [of Dungeonland and Land Beyond the Magic Mirror] opened the door for the later WG7, Castle Greyhawk (1988)."
Since the article contains numerous factual and interpretive errors about the history of the hobby (such as not knowing who Eric Shook was, for example), it's easy to dismiss as errant nonsense, but it speaks volumes about the long shadow Gary casts over this hobby. He was a colossus and it's perhaps unsurprising that so many people wanted to "expose" him as having feet of clay. It's regrettable that Castle Greyhawk was ever published. Whether or not it was intended as a jibe against Gary, few can say, but I think it's certain that this module was ill-conceived, badly done, and a slap in the face of Greyhawk fans, who'd been hoping to see more of the real Castle Greyhawk, a dream that remains unfulfilled over 20 years after the release of this module.