In it, you control a party that sets out to defeat Uukrul, an evil wizard who took over the city of Eriosthé. His main power is in the ability to freely phase between the mortal plane and the astral plane, and that power is held in the titular dark heart, which is stored in an urn in the catacombs between the city, and is obviously heavily guarded to boot.
Dark Heart of Uukrul contains examples of the following tropes:
- Apocalyptic Log: The manual included the diary of the previous, dismally failed, attempt to defeat Uukrul.
- Arbitrary Headcount Limit: The party consisted of exactly four characters - one each of the Warrior, Paladin, Cleric, and Mage classes.
- Blob Monster: The Amorphous Globs.
- Copy Protection: In addition to any on-disk copy protection, the feelies included a black-text-on-maroon-paper code book used to unlock the Sanctuaries (which were the only location in which you could save your game). Also, casting spells required you to type in the spell name from the user manual.
- Crossword Puzzle: One area of the game featured one of these; the solutions were used as passwords for secret doors.
- Dungeon Crawling: The entire game takes place in the underground city of Eriosthé.
- Expy: The 4 Gods the Priest prays to for spells ("invokes") are visibly based on the 4 Chaos Gods from Warhammer - Ufthu on Khorne, Drutho on Slaanesh, Golthur on Nurgle, and Fshofth on Tzeentch.
- Final Death: A failed attempt to resurrect a character resulted in the destruction of their body. The longer a corpse stayed dead, the more likely a resurrection attempt was to fail. In the event of a Total Party Kill, the party's corpses would remain where they fell until other (abstracted) adventurers came along and dragged them back to the "safe" part of Erisothé to be resurrected.
- Mana Drain: The Mage's Sator and Rotas spells.
- Plot Coupon: Uukrul's own heart, and the fossilized hearts that act as keys for its storage container.
- With This Herring: The "we're choosing you because the Big Bad can't possibly have heard of you" variant.