Total Annihilation is set in the distant future, during a civil war in humanity between the Core (Transhumanist cyborgs) and Arm (Humanist rebels) forces. You play as the commander of a force on one side or the other with an array of units at your disposal from various construction buildings, each of which can be upgraded into an Advanced form, and your chief resources are metal and energy, both of which can be harvested from your environment (Including metal from the remains of fallen comrades & enemies).
Of course it's an old game so the graphics aren't exactly amazing, but the gameplay remains pretty solid. My one legitimate complaint really is that computer AI during campaign mode at least, it seems to toy with you occasionally and definitely decides to overwhelm you if it can regardless of how far into the match you are. (Darn that AI with it's dozens of Warlord battleships...dang harbour)
Total Annihilation was made by Cavedog, also responsible for Total Annihilation: Kingdoms (A fantasy-style reimagining) and several expansions for both. While Cavedog was short-lived as far as games developers go, it made some real classics in my opinion, and you can now happily download Total Annihilation for little if any cash on a variety of sites online.
I will warn you though, the cheats don't work in campaign mode, even against the malicious cheating Core forces
