Raiders of the Forbidden Mine

Raiders of the Forbidden Mine (also known as Raiders of the Lost Mine, Diamond Digger and Gold Miner) is a real-time action game with gameplay and a third-person perspective reminiscent of Dig Dug and Paganitzu. The objective is to collect as many gold nuggets as possible by maneuvering the player character through a series of levels situated in an underground mine while evading enemies capable of killing upon contact. Each level contains oxygen boxes to ensure the player character does not run out of breathable air and a key needed to unlock the door to the next level.

Source: Wikipedia, "List of minor Apogee Software video games", available under the CC-BY-SA License.