Warhammer 40,000: Dawn of War

In Warhammer 40,000: Dawn of War, humankind must defend itself from ancient enemies in a world of treason and conspiracy. 

Now, as one of four different races, you join this fight to rule the universe. In the single-player campaign, your troops have access to a variety of melee and ranged combat moves. This RTS puts you in charge of the Imperial Space Marine Chapter "Blood Ravens" as they try to contain rising numbers of Ork invaders on the planet Tartarus. 

Leading your forces through an epic single-player campaign with eleven scenarios you discover the true reason for their presence on this world, and find out which roles the evil Chaos Marines and the mysterious Eldar play in this affair. Practice your best strategies in head-to-head or cooperative multiplayer action. Two to eight people can battle it out through the Internet or a local network. 
Take to the skies as all armies gain new air units to rain death from above.Wage war across an entire solar system. Liberate, enslave, or destroy entire worlds as you unleash your army's fury on an interplanetary scale