Hi guys!
So I've been playing Dungeon Keeper 1 for a short while now and i have reached the tutorial level in which you fight against another keeper for the first time.
So i went to his dungeon heart and dropped all my minions there, but they could not attack the dungeon heart as there was one imp directly on top of the dungeon heart and my minions just focused on him although he wouldn't die.
Because of this i could not attack the dungeon heart directly and all my creatures died after a while because the imp killed them all.
So how do i fix this? Is this a bug or do i have to do anything else apart from attacking the dungeon heart?

Are you sure you're playing the first level? Because, from the description you gave, it sounds like you're playing the bonus full moon level. The story levels have a T inside a circle, whereas the full moon level has a white circle (full moon). You may also be playing the Deeper Dungeons expansion.

If you are, indeed, playing the right game and the right level, then I would recommend leveling up your characters in the training room before sending them to do battle with the enemy, as their minions are a bit stronger than our default level 1 creatures.

I honestly don't think that's a bug, at least I never heard anyone mentioning it. Old games were hard and didn't exactly tell us what to do next. We had to read manuals thoroughly. Fortunately, the GOG version of Dungeon Keeper comes with a PDF manual, be sure to read it if you're having trouble playing the game. It should be in the folder where the game is installed.

The same thing happened to me yesterday, and like TheKayGamer said, it was "the tutorial level in which you fight against another keeper for the first time" aka Lushmeadow-on-Down, the fifth level. All of my minions were gathered around the enemy's dungeon heart, and I could hear some of the sounds of combat, but they didn't seem to be doing any damage to the heart. There was also some sort of creature (possibly an imp) on or near the heart (hidden behind a column), but it wasn't taking damage either. I waited for at least twenty minutes before giving up.

I rushed without training my warlocks into ranged attackers, so it's possible that groze's suggestion to train more would have helped, but if so, it's a targeting issue and not a matter of having insufficient force.

I have all the latest updates, so this is definitely still a bug as of May 2019.

I have seen a couple odd behaviors around an enemy heart but not this one. I have seen creatures hitting and damaging their colleagues while swinging at the heart for instance. Imps turn around and fight if they are near the dungeon heart. No fleeing from there.

You could try possessing a minion and seeing if you can hit the heart in 1st person.

Using warlocks is common, almost required, in that level since it's still one of the only creatures, do train them though because their melee is garbage.

GOG is not doing any bugfixes, so it will stay a bug.

When enemy keepers create new imps, they do so from the dungeon heart. If you have 'imprison' enabled and units in place attacking his hearth you might 'faint' the imp right over the dungeon heart. It now has 0 health but you can't kill it. You have three options:

- Get one of your imps to carry it away to your prison
- Allow it to wake up and walk away before attacking again.
- Disable imprisonment, so that when it wakes up you will kill it.

A fix has been created in KeeperFX Unofficial, but as of today that fix has not been released yet. What happens after that fix, is that if a unit hits an unconscious unit, that unit moves based on how hard it had been hit. So fainted units are moved out of the way after a single hit. If you want to play with that fix, update to an alpha version of keeperfx unofficial.