I <3 Watchmen
How ever, halo wars will be another story.
You get to choose between 12 giant powers which represent absolutely no challenge to play as.
In previous games, you unlock minor factions as you conquer them. But according to CA, this is not the case with ETW.
And they decided to have Steam automatically check the integrity of the games files and if you unpack them or edit them, Steam automatically fixes them to vanilla.