DOW is a good enough game for RTS fans out there. Harking back to the good old days of Command and Conquer, it takes resource management and troop building and maneuvering to accomplish each level successfully.
The learning curve isn't hard and you don't have to be a tactical genius to progress through the game. In fact, the simplest tactics often work for all the levels. For example, building up your base and slowly massing your forces before breaking out to massacre the enemy is often the only tactic you need. A couple of levels require you to accomplish goals before a set time limit, but there really isn't anything remotely challenging here.
That said, the game is enjoyable, if prolonged. Although only about a dozen levels in length, each one will take a few hours to complete. You could probably do them quicker. If anything my only fault was building too many units. When it came to the fights the enemy was slaughtered by overwhelming numbers.
The most useful unit in the game are undoubtedly the defence turrets. Start building those around the edge of your base as soon as you can and you can sit happily inside and build men and dreadnoughts to your hearts content as the enemy throw themselves inanely at your automatic defences. Keep a couple of mechanic units around to make running repairs and little will trouble you.
This is also the best way to deal with the occasional "Big Boss" that appears. Beef up your turrets and have a few squads of men behind them, then send out a squad to lure the level boss in to your killing zone.
As mentioned, the enemies aren't very smart, throwing themselves against your impenetrable wall of lead and plasma time and again. It would have been nice if they could have come up with better AI, but hey, it is a Games Workshop device to draw more players to the table-top version of the game. Draw them in, and have them spend ridiculous sums of money on the figures and "official" paints etc. So a difficult game would have been a non-starter.
Anyway, despite these gripes the best part of the game as far as I was concerned is actually the opening movie. This is, without a doubt, one of the best animated sequences I've ever seen and I never tire of watching it whenever I start up the game. If only they'd put a few more of these throughout the game, instead of the lame, overly long dialogue and cheesily animated characters they do have between levels.
In summary, good enough if you want something non-taxing. But don't look for much depth or skill.
EDIT: Wow! This is one of my most hated review ever! I guess Games Workshop fanatics are even more dedicated than Scientologists at rubbishing objective viewpoints :)