There isn't any story crossover, if you are looking at buying 2 make sure you read the sticky thread regarding PC compatibility as there are still some issues.

I believe the 2 version provided here by GOG is flawed, I see too many people complaining

Dungeon Keeper 1, imo, is the better game. But that's with Deeper Dungeons included (a pack of stand-alone levels that were more difficult/more interesting). I don't think GoG's DK1 version includes Deeper Dungeons, and if that's so, then...DK1's original campaign was ok but takes a while to get going..the later levels are the better ones.

Anyway...I know this is an old post/question...just putting my opinion out there. :)

DK1 has dragons - DK2 has wimpy salamanders.
DK1's vampires don't care about water. DK2's vampires melt in water and DK2's AI=vampires who constantly injure themselves by walking on the edges of water even when you build bridges.
DK1's scripting and editor are much more fun to mess around with, imo.
DK1's training room lets you train to max creature level. DK2's training room lets you train to lvl4 and then you have to use a combat pit (which is awkward and distracting outside of pet dungeons).

DK1's one big weakness (to some ppl anyway) is that you can just drop creatures on top of a fight willy-nilly. DK2 tried to "fix" this by making creatures stun when dropped. However all this did was make you drop creatures a few tiles away instead...both games are still largely about having better numbers/higher lvl creatures than the other guy and/or acting faster than the enemy.

Best thing about DK2 was the pet dungeons, and the fact you could build rooms in much more oddball configurations/sizes since they removed the need for "efficiency."

Both games have poor enemy AI, but I think DK2's enemy AI (especially in skirmish) was even worse. At least in DK1, with scripting tricks, you could make the enemy dungeons be at least a little difficult to work through.

I still play DK1 (CD disc Gold version). I don't still play DK2.

Dungeon Keeper 2's graphics are a little bit better/different, but that's really the only thing that's better about the game. Even that's debatable though, because i think the creatures in 2 look absolutely terrible.

The gameplay of the DK1 is more varied and in general faster and more interesting. I don't know what it is about the second game, but it somehow lacks the clear gameplay of 1. It's such a terrible clusterfuck when it comes to bigger battles. 1 has also more creatures to do your evil bidding and even controllable Horny's. The creatures of 1 are also a lot tougher and aren't so squishy like in the second one and therefore making the battles more interesting.

-> DK1 is the better game.

I just wished that gog would put deeper dungeons on the site. The problem I found with dk1 is that it is too easy for too many levels. If you play completely blind then the ending levels are a better challenge, but if you know what you're doing, they can be made much more simple. I found that when I was playing dk2, once I had horny available, I barely had to do very much work really. The last level was a joke, because horny did pretty much all the work.

Just FYI, there are legal problems with several EA expansions, unfortunately. :/

Dungeon Keeper 1 (with Deeper Dungeons) is far better than 2. Dungeon Keeper 2 has far too many flaws to even be considered a good game. None of the levels are challenging, creatures 'bump' into each other, which makes doors in your own dungeon pointless because creatures effectively go single file, you need huge hatcheries, fighting is too easy once you have acquired lightning, the GoG version is buggy, there are no tactics apart from conquer everything (and even then all you need to do is target the Lord of the Land on most levels), the graphics in my opinion are far worse than DK1 and it takes far too many levels to actually be able to use everything (I think you get the temple in level 17?!)

DK1 just feels like a masterpiece. Agreed there are parts of it that are buggy, but on a whole the game is a challenge. There are levels that when you complete you feel like you've been through the ringer, you can wall yourself in or choose to fight open, traps feel effective (despite a door-boulder-door-boulder/guard post-lava trap combination), you actually get low on gold and it makes you take decisive action. The levels are brilliant.

He's probably made his decision by now...

oh no my friend he may not have, some people take time in their decisions and become sage like :p

I recommend playing Dungeon Keeper over Dungeon Keeper 2. It's easily one of the best strategy games ever made.

And now we have another person doing it.

If you bury a bunch of dead discussion threads in your graveyard and piss on them, a special vampire thread emerges that is literally immortal after a certain level

They suck all the ageless blood out of every discussion they touch.

Probably a bit too late by now, but for future reference:

Both games are fun, for me the clear flaw of DK2 was that the AI just isn't as challenging as DK1.

Apart from that you can't go wrong with either game,wait for a sale (I've noticed that the series goes regularly on sale) and pick them both.