I'm on the "Scavenger" map, and having discovered the already existing Graveyard, no matter what I do, I was only able to raise one vampire there. After I dug out the walls, and built it up to maximum size, two more coffins appeared (I think those green-ish things are coffins, anyway) but they later disappeared when I was looking elsewhere, and I still only had one vampire (despite killing a good amount of enemies, I couldn't watch the Imps all the time, but at least some corpses should have been gathered). The walkthrough over at https://gamefaqs.gamespot.com/pc/176198-dungeon-keeper-2/faqs/28284 claims, they the discovered Graveyard's base size should support up to 8 vampires. So, what's going on there?

And while at "Scavenger" map, are any of the capturable Good units there able to work in the Workshop? I was thinking to place some doors to stop the Imps from going off where I don't want them to and getting killed, but neither the skeletons nor the vampire didn't want to work there. Captured dwarves weren't doing that, either.

Only corpses that fall and rot on the ground will go to the GY.
I notice you mention skeletons; you have to have your Prison off to make Vampires. I don't think it even takes corpses that die in the Torture Chamber.

I think I just failed to have my imps collect the corpses.

Playing the map again, I got about three vampires, not that many, but I managed to beat it anyway.

Oh, and imps can drag the corpses of prisoners who die in a torture chamber to the graveyard, I've seen them do that many times since.

I got to the last level, and was able to close all the portals heroes were coming through, while also building the sizeable army from the conversted heroes, but then had hell of a gold trouble, which creating gold with magic couldn't keep up with, and majority of my army deserted before I found the gems.

Well, I can't be bothered to deal with the drudgery of handling that again, that level looks like it'd be a crappy grind against lots of traps and other fillers, which could just be an annoying way to slow me down. So as far as I'm concerned, I consider the game finished, I'd be able to do that, but the map is just too dull and annoying, once you deal with the attacking hero waves.

For anyone playing the final level in the future: if you can manage it that way, avoid building the training room, leave one hero portal active, and have your creatures train on the endless waves of low level heroes, who will keep coming.
(which will also let you recruit some heroes, and use the rest to get some skeletons and/or vampires going)

Nah, I took the prisoners, tossed them into torture chamber, even not having any skeletons at all (they are weak, I rarely bothered with them), and my imps dragged their corpses to the graveyard regardless.

Unless you meant the heroes who die in prison? Maybe, as I said, I never cared about skeletons much, so I don't think i ever reached the limit.

As for the final level and Horny spam, that doesn't sound like much fun, either, so that makes me glad I left it there.

Still, most of the game until then was fun, and I don't regret playing it.

Yes, so normally with imprisonment on you don't get much vampires. You get to rescue your own units, prisoners either turn to skeletons or get converted to your side.

So only if you miss a beat will you get the vampires, or when you turn imprisonment off.

If you liked the game, try the first one. I'd say most people who played both prefer the first game. Personally I would say the first one is a lot more fun, certainly not as slow paced.
You'd need to use KeeperFX with it though, the dosbox version of GOG sucks.

Prisoners only lived long enough to convert if I healed them first.
If I tossed them into torture chamber without healing, they died before they could convert (and revealed some map area, so it wasn't for nothing).

Oh, and I already finished the first game, but thanks for the recommendation. :)
(for me the DOSbox version worked just fine, though, as far as I remember, it's been a while)

Comparing both titles, my perfect game would take some stuff from each, f.ex. the way workshops work from DK2, but training of creatures from DK1.

Yes, DK2 certainly had some improvements. It's a real shame it also had several things that were worse, and that there never was a third game to take the best of both games.

It’s debatable of course, but in my opinion War for the Overworld is the closest thing to a Dungeon Keeper 3 you can get.
It plays like an improved Dungeon Keeper 2, I can’t say if it brings back some better things from the first one that I don’t know that well yet.

For me, no. War for the Overworld was designed by somebody who loved to play DK2 in multiplayer, and he just looked at DK2 for inspiration. The original campaign was also just quick high-pressure levels.(I've heard later patches provided new campaigns that focused more on dungeon building as well). People who only or mostly liked the first game, will not care for WftO much.

sorry if already mentioned, I didn't read the whole thred. Yes corpses of the Torturechamber do contribute to the graveyard, if you have idle imps collecting them or you just pay a lil attention to the narrator and throw an imp there when you hear him say "an enemy hero has successfully been interrogated in your torture chamber".

Thanks to your post I spent some time on the original Dungeon Keeper lately, and now I understand how War for the Overworld takes a lot from Dungeon Keeper Ⅱ but not so much from the first one.

I actually love some specificities of the original Dungeon Keeper, especially the unbreakable fortified walls that completely change the way you design the dungeons, including the traps and doors.