I am aware. I have been playing D&D since 1979 and have played all the versions of the game but OD&D and 4E. I wasn't aware that it was necessary to give my resume in every post.
Sorry, no. It’s not necessary. I apologize if I implicitly questioned your experience. I can only reply to what you wrote. I don’t agree that devising a DC is the same deriving from the monster’s HD. It’s different, and it’s one of the things that appeals to me about OSR games versus “modern” ones.
So what?
I can pick up the Caves of Chaos and run it without effort under Shadowdark. That's compatible for me, in the sense that "I can run this at the table without real effort."
What does that mean? I’m not being snippy or trying to pull a gotcha. The GM quickstart doesn’t have anything to say about using other adventures. In my mind, there’s a difference between compatible and requires conversion — even minor conversion! It’s any indicator of how much work I can expect to do when using monsters or material created for a different game.
If it’s just substituting monsters (and using discretion regarding DCs on ability checks), then that seems more like conversion to me. My rule of thumb here is if I can do the same thing using Pathfinder 2e, then it seems more conversion than compatibility to me.
Compatibility is not a religious dogma. If you want everything to exactly match BX, then only BX and its retroclones are truly "compatible." And when we get to that point, every other OSR game is incompatible.
But that's also demanding a level of compatibility beyond how people actually played AD&D and BD&D. It was incredibly common for people to play a BD&D adventure with AD&D rules, despite slight numerical differences between the two rulesets. Only Gygax on his bad days thought this was a problem.
I gave the example of Worlds Without Number, which is a game that has different numbers. They’re close (like your mixing AD&D and D&D example below), but they’re different, and the categories are different. My point here is that “conversion” in this sense is just swapping one number for another. The resolution process ends up working more or less the same.
See above regarding compatibility. I should note that I’m not talking about how people actually played but OSR the retrospective movement based on a particular style of play plus also looking at the classic games and analyzing what their mechanics suggest about play (particularly when it comes to NuSR games).
They have a complete set (including every single printing, so it's a very aggressive version of "complete") of the original adventures, followed by a 5E update. So the original versions of In Search of the Unknown and Keep on the Borderlands in all their BD&D glory are in Into the Borderlands in addition to the 5E.
So I am talking about running the originals.
Oh, okay. Thank you for correcting my misunderstanding. I did at least try to check what Goodman Games said about those adventures, but I was wrong.
No, that's not what I'm saying at all.
I apologize for the accusation. I thought you were talking about 5e versions of adventures. Obviously, what followed was wrong.
I'm coming at this from the perspective of someone who actually DMs games, rather than hoards RPGs, and I'm saying that I can grab a BD&D or AD&D adventure, or an OSR adventure, and other than having to do a simple swap on monsters with descending armor class, I can run the adventures in Shadowdark without effort.
Anyone who is concerned that an ogre's armor class might be a little off from what it says in the rulebook is invited to find a different game where they're more comfortable.
This gets back to my question regarding conversion or compatibility. I suppose it’s just semantics though.
I don’t think the different AC numbers are a big deal. It’s something worth noting I guess, but the other things would be issues for me. I wouldn’t like to have to devise ability score arrays for every monsters I was converting.
Update: I consolidated some of the quotes to avoid looking like I was nitpicking line-by-line. That’s not the intent.