So far, I can't claim to have played this long enough to have reached far in it.
But I know the basic idea of the game.
Some context is in order. The game got a rather negative reputation because people expected it to play like Dungeon Keeper. Instead, the first Dungeons plays more like a park simulator. This misconception led to many players being extremely disappointed.
However, despite not being Dungeon Keeper, the game is fun in its own way.
Your objective is to provide the Heroes entering the dungeon what they want, whether treasure, weapons, spellbooks or monsters to fight.
Only after they are satisfied, the player is to send the Dungeon Lord to take out the Heroes so they can be imprisoned and their soul energy can be harvested. The more content the Heroes, the more soul energy capturing them yields.
Soul energy in turn is required for improving the dungeon and increasing the power of the Dungeon Lord.
At the same time, the player has to be wary of those Heroes who might try to destroy the dungeon heart.
And of course, everything is done with a highly humorous tone and references to other fantasy series.
This might be the lowest rated game of the Dungeons series, but I don't really care. I'd preserve this for those who do/did enjoy it.
And besides, every other title of the Dungeons series is on GOG.com anyway.