Regarding the sound design, I think DEFCON had really great music and sounds for this type of game -
http://www.youtube.com/watch?v=mCpVpIBqaJg. I hope you are taking Command sound and music design to this direction.
Quote from a review:
One of the most chilling aspects of Defcon is the subtle ways it suggests that it's more than a simulation, something it does almost entirely through sound design. The sounds that accompany the action are appropriately blippy, and there's definitely something sinister about the Klaxons that sound when you reach a new Defcon level, but it's the ambient sounds that really set the mood. There's not so much music as there is a drifting, ominous instrumentation, and mingled with these dark sounds are the light hum of computers, the hollow wash of recycled air, some indistinguishable radio chatter, and the faint sound of someone coughing. Or is it crying? The ambient sounds end up looping after a while, but that doesn't lessen their effect of making you feel like you're holed up in a bunker, helping dictate how the world ends through a remote computer terminal.