Its not really a RTS game entirely. Its kinda like a mix of Diablo and single player starcarft mission were you only control a hero and some regular guys with no base.
Eventually if DOW2 you get basically 4 squads of guys I think, each squad is lead by a hero and has a few generic members. I don't know if you any bit famialr with Warhammer 40K space marines, but you basically get a tactical squard, a devastator squad, assault squad, scout squard and a dreadnought eventually. I believe you can take 4 of 5 squads though on missions. Through out the level there kind of like checkpoints you can capture that will let you replenish dead generic squad members. The heros leading each squad level up and skill points, plus get dropped loot to equip on them. They also get special abilities you can use. The heros can never die, but if lose all there health they go down and only the heros from your other squads can revive them. If all your heros go down you lose the game.
I enjoyed the game for its time and had a lot of fun with the campaign, including the expansions, but I am a 40K fan in general. I think I enjoyed the single player campaigns in this game more then the first game. I wanted to replay is recently but I couldn't remember Game for windows log in, so I kinda gave up. I was gonna give it some more time and see if this games loses that requirement and try in the future since GFWL is supposed to be gone later this year.