Fighting Fantasy: The Warlock of Firetop Mountain
The basic game premise hasn't developed a great deal in the 27 years since: the player still controls the actions of a mercenary (in attitude, if not profession) adventurer in a medieval / fantasy milieu (canonically, the environs of Allansia on the world of Titan). Debarking from a water voyage, the player learns of fantastic treasures strewn through the defunct dwarven mine atop nearby Firetop Mountain, now inhabited by the dire warlock Zagor and his coterie of foulest orcs.
Parting from its somewhat automated hyperfiction origins like the Deathtrap Dungeon FF conversion, the player instead navigates a fully 3D environment from a first-person perspective, albeit one populated by 2D sprites of enemies and NPCs. The Fighting Fantasy player statistics of SKILL, STAMINA and LUCK come along for the ride, though additional stats and metrics have fleshed out the RPG system somewhat.
Many encounters are randomly generated, and to maintain challenge levels, monsters escalate in difficulty over the course of gameplay such that even while backtracking through previously-cleared areas the player will randomly encounter tougher enemies than the ones just wiped up. Hopefully the player will also encounter the two disparate keys required to unlock Zagor's treasure trove.