HeroQuest and Warhammer Quest are probably the 2 best know of a group of games published by Games Workshop that share the theme of Dungeon exploration (only slightly less well known is Advanced HeroQuest and then we get into more obscure games like Mighty Warriors)
The basic theme of all these games is that 4 or so players take on the role of a party of Heroes while another takes on the role of Game Master. The Heroes explore Dungeons together killing Monsters and collecting Gold. At the end of each game the Heroes can then spend their Gold on extra Weapons and Equipment so they can more effectively explore Dungeons, kill Monsters and collect Gold. The Game Master (or GM) lays out the Dungeon as the Heroes explore and controls the Monsters which the Heroes fight.
While HeroQuest and Warhammer Quest haven't been available for many years and are no longer supported by GW, they are still fondly regarded by many gamers, are still played today and have quite a following.
although GW don't do any 'Dungeon Crawler' games at the moment there currently several similar games available from other companies.
Descent: Journeys in the Dark is published by Fantasy Flight Games
CaStle RaVenLofT and
Wrath of Ashardalon are published by Wizards of the Coast (current owners of D&D and makers of Magic: The Gathering)
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~The ravings of a single mad Goblin is bad enough, but such a power-hungry, malice-filled creature as Mortis can never hope to be understood~