THE GREAT OLD ONES is widely acknowledged to be one of the best products an early Chaosium put out. Having had it recommended to me, and having been able to chase down a copy, I can say that the adventures look interesting, original, and well-researched, although somewhat primitive in their development. I think all 6 of the scenarios would be fun to play or to run. They can be run separately or as part of a continuous campaign.
"The Spawn" - The "Broad Vein" and "Copper Lady" are adjacent mines in Coppertown, NM. One is producing loads of rich ore, and the other is losing money. But it might surprise you at which one the miners are given easy hours and high pay. It certainly surprised IWW, the big union of the 1920s. When one of their undercover agents is killed, the other calls on the investigators for help. There's more than one way for them to discover what lurks at the bottom of the mine, and at least one involves them not leaving again.
"Still Waters" - Many investigators are book hoarders or bibliophiles, always trying to get a leg up on the next tome. They are supposed to meet fellow enthusiasts to look at a unique tome, but the family has disappeared. Clues lead to an archrival, a mask covering a horrible face. Talk about not judging a book by its cover ...
"Tell Me, Have you Seen the Yellow Sign?" - Being a King in Yellow afficionado, this scenario really appealed to me. Plus, it is set in Mardi Gras. How fun! And as we all remember, New Orleans was the site of the last victory against the Cthulhu cult. Perhaps there is more here than meets the eye?
"One in Darkness" - The baddie you have to fight here is a god. Good luck!
"The Pale God" - What an opening scene - describing it would take away some of the punch from playing the scenario, but if you know Ramsey Campbel then you know what is coming. Most creepily, the little white things are everywhere throughout the scenario - How exactly do they infect and infest? This could lead to some brilliant paranoid roleplaying.
"Bad Moon Rising" - The first half of this scenario is an excellent conspiracy game. I'd move the time forward some and use it as a Delta Green scenario; maybe set in the 1940's when it was OSS, or maybe early 50s when it was still legal. The British Navy is hiding something, a secret installation that has already cost the lives of four men. Can the investigators get in on the action? They'll have to be practically black ops to do so, but the rewards are worth it.
There is a distinct second half of this scenario that the keeper might want to adjust. Whether it should be a dream, or shared delusion, or some twisted reality, I don't know, but it doesn't seem to fit witht he first half. Maybe just run the first half without the second? Actually, with a different introduction, the second part could stand on its own. I have the feeling that the latter was added to the former for the purposes of having a GOO (and thus being appropriate for inclusion).
Well, THE GREAT OLD ONES definitely has some great material. It has plenty of convoluted plots, deadly encounters, and chances for players to show their stuff. I think keepers will also have to develop some of the empty space on their own, depending on their players. Well, roleplaying should be fun for players and keepers too.