Myth: The Fallen Lords -- Mission 11: Silvermines
An old RTS game with good replayability, Myth: TFL was an unheralded success, becoming one of Bungie's greatest assets before their sale to Microsoft.
The graphics engine utilized in this game was subsequently used, or modified, for the next two Myth games: Myth II Soulblighter, and Myth III The Wind Age.
Here is a no-casualty run of the Silvermines level. Difficulty level was Normal.