This add-on adds 16 new single-player missions, 8 for each side. Unlike the main game, there is no storyline to connect the missions, so they can be played in any order. Several new campaign-only units are available, including the Soviet Tesla Tank prototype (featuring a mounted Tesla coil as its weapon), cybernetic super soldier Volkov and his dog Chitzkoi, as well as some older units upgraded with nuclear weapons.
Counterstrike also includes more than a 100 new multiplayer maps and new music tracks composed by Frank Klepacki.
As a hidden bonus, a small "Giant Ant" campaign is included, featuring combat against gigantic mutated insects in true 50s B-movie style.