Decided to take a quick detour from Darksiders 2, and i've completed the first Dawn of War campaign, which I'd never tried.
I think tha Dark Crusade and Soulstorm expansion campaigns are much more famous, because they give you this large map that you can tackle in any order, and you can play any faction you want, but this one is a linear mission-based campaign, where you only get to play as the Space Marines.
And yeah, its your very typical Space Marine story: A planet is under attack by Orks. You come in an kill a bunch of them. The Eldar are also there fucking about, whilst being super vague and mysterious about the real threat. Then surprise! the Chaos Space Marines are behind the whole thing, and serve as the big bad. Throw in the innevitable betrayal of one of your allies, and hey presto, that is Dawn of War 1's campaign.
Honestly, from a story perspective, if you've played one, you've played them all. Specifically, Dawn of War 2 (except it is Tyranids instead of Chaos) and both Space Marine games come to mind.
As for gameplay, there isn't too much variety here. In each mission you build your base, and then either capture points, or destory the enemy base, or both. I think StarCraft 2 has me spoiled for what RTS campaign variety can look like, but at least this one is comparatively short.
So yeah, that is Dawn of War. Its fine. I'll probably also do Winter Assault, because i've never played that one either.