I feel there are a few nice twists. You can recover new technology and design new vehicles and defenses. The game play is a little harder than C&C right from the start. The best part is that it is free.
There are a few draw backs, but not many. There is a manual, but it is not as slick as commercial games. A few odd keystrokes and you are moved to a different part of the map. Surprisingly installation for Ubuntu was very easy with the supplied package. There is a Windoze and a Muc installer, but I have no experience with those.
This game is highly addictive; so addictive in fact that I am going to cut this post short and play.