I've seen excellent quality in the Silver Anniversay editions of The Keep on the Borderlands and White Plume Mountain, which makes me wonder how this one snuck under the radar. The promise behind these modules is that they are going to be retrofitted with logic, plot, rounded characters - qualities that sometimes lacked in the classic originals, but are demanded by today's players. The implied promise is that they will expand upon the original material, or take it in a fresh direction. That did not happen in this module. The first three giants modules (which I already bought from a used book store) inserted -intact - into the module. Guys, if I'd wanted the original modules, I'd have bought the original modules. I bought Silver Anniversary because I wanted more. Packing a lot more of the same around the first three modules intact, does not really expand upon my gaming experience.
Essentially, the rest of the Duchy of Geoff is packed around the 3 original giant fortresses. But this makes the module into more of a "world book" than an adventure module. There are X number of towns to liberate, each with a different kind of giant and smattering of orcs. But it's all much the same, and frankly, after the first 3 modules of giants, giants, giants, the rest of it will get tired quickly. There is a half-hearted attempt to provide a new motivation for the original giant attack on the Duchy of Geoff (a new villian) but strangely, the old villians still exist in the 3 intact main modules, with no acknowledgement of the new villian or motivation (and no interface for the players to discover it, in game). The DM notes offer a flake of bad advice on how to use the two kinds of villianous groups, explaining that they should use them to confuse the players. Without a good reason for either of them (the new villian's motivation is shaky, the original villians were just evil), the confusion is just frustrating. DM's need to do major tweaking of the plot to fix it.
Further, the giant combats get tired after a long time for players who want to play anything other than a skirmish game. If you like traps, tricks and thinking, forget about it. If you like flat out combat with lots of bad guys, here you go.
Finally, the story fails. I cannot accept, within the context of the Greyhawk world, that all the armies of Geoff were killed off by these giants, and that only a single party of adventurers will single handedly win the war. To patch it together, I've popped in a workable backstory, and I'm trying to put together an army to function as a backdrop for the characters. The players choose the general tactics of the army, and then take out key areas of the giants -commando style. It is clumsy though.
I'm going to fast forward through parts of this module, and get to White Plume Mountain as fast as possible.
Save your money and buy something else. There's not much here worth playing.