Tunnels of Doom

Tunnels of Doom is a role-playing video game programmed by Kevin Kenney for the Texas Instruments TI-99/4A home computer and published by Texas Instruments on December 31, 1982. It was available in two formats: cartridge with accompanying disk and cartridge with cassette.
Based loosely on the tabletop role-playing game "Dungeons & Dragons", it is a dungeon crawl in which players control the fates of 1–4 characters as they navigate a maze of tunnels. Texas Instruments used the game in its marketing, citing it as entertainment software involving "strategy and logic".
Gameplay.
The game has four character classes: hero, fighter, rogue, and wizard. In a single character game, only "hero" is used.
Upon encountering an enemy, the game transitions to a separate, graphical, overhead battle screen, where a tactical turn-based combat system is used that allows for movement and positioning. It's possible to listen at doors for sounds of monsters, which can be negotiated with in combat as well.
Legacy.
In 2008, Howard Kistler of DreamCodex developed a revised version of the game with the permission of Kevin Kenney.