The Keys to Acheron

_The Keys of Acheron_ is the first expansion module for Hellfire Warrior. The
title refers to four gems that the player must recover at the request of the
wizard Abosandrus, to prevent an invasion of the demon lord Kronus. These gems
known as the Keys of Acheron have been scattered across space and time. The
result are four new game levels, each with their own new set of creatures,
traps, and hazards:

* Abode of the Dragon. The Key hidden there can be recovered by facing the dragon directly or finding a secret passage. There is also a unicorn there that may provide a useful item.
* The Temple in the Jungle. A primeval jungle, various dinosaurs and quicksand can be encountered here, among other things.
* The Crystal Caves. A dead volcano, jets of steam and fungus man are among the dangers.
* The Shadowland of Kronus. A dark world of the far future. Features the Black Sea with the Kraken and tall waves.