(As far as I know) The biggest difference in the (known) two printings of The Mines of Keridav is the Publisher of course.
Phoenix Games was the original Publisher in 1979.
Gamelords published a 2nd print in 1983, under their mark.
I believe that Phoenix Games also published The Demon Pits of Caeldo at an earlier date.
Reason being is that the Mines of Keridav is labeled "Role Playing Scenario #2" at the top right corner of the front cover.
I think that The Demon Pits of Caeldo was probably "Role Playing Scenario #1".
I have no proof of that though as I have never seen it and the Gamelords versions list a Scenario Number for the two adventure books.
However, there is good evidence that it was already published before this one was.
On pages 8-9 (of both prints) there are stats and details for the ground level entrance to Castle Caeldo and the highwaymen that will ambush any group that comes close to it.
The other adventure "The Demon Pits of Caeldo" also has that data, but that book also includes all of the data for the lower levels and the castle itself.
Otherwise....
The differences in content?
Mostly aesthetic... See below.
1) The front cover artwork is a totally different picture.
2) The addition (in the 2nd Print) of Thieves Guild Stats for the characters in the adventure as published by Gamelords in 1983.
This added four new pages to the back of the book.
3) Another difference is that the MAIN game maps were totally redone; especially the color map on the rear cover of both books.
And the center four-page map insert as well, though to a lesser extent.
And
IMO they were not made better by the changes either.
I much prefer the earlier Maps by Phoenix Games to the so-called updated maps by Gamelords...
In each set of pictures below, the 2nd print is on the left with the 1st print on the right.
With the center fold maps, the 2nd print is posted first, and the 1st print is below that.
(I had them side-by-side earlier, but the width added a page scroll, so I stacked them)
For the other maps, not much difference really.
The 2nd print maps are on regular paper and are in B&W print, and the 1st print maps are on a glossy magazine sort of paper with brown black and white print.
