Quake and Conquer, by Ryan Dobson — a Real-Time Strategy Game Set Inside the Quake 2 Environment

"Take all the techniques you know about Quake 2 and throw them away. Quake and Conquer is all about resource management and strategy. You can't resort to a gung-ho solo charge because - well, you just can't. Your player is a disembodied essence wandering the levels. You have direct control over your creatures and machines through your crosshair."