I had the previous original game Order of War, so in my case I did not have to purchase the Challenge. I guesss that the guys who have to download it from Steam and do not have the original, will pay around 10 bucks. I started playing right after it was out a few days ago. I would say, my impressions are pretty positive. The developers have included the features, which, according to me, were missing in the original, such as the Fog of War and several new playing modes. I personally liked the modes Survival and Free for All. It was also quite fun to play because of the new people who purchased Challenge for 10 bucks, which I think is not much for such a good RTS multiplayer. So, in general, (although I did first have some troubles with the original game) Challeng is Ok.
I think the good thing about this addon is that you dont need to purchase the full singleplayer version if you are not keen on the idea of singleplaying and you dont need to buy the original, which is not that cheap, you know.
This game has a similar interface to World in Conflict. It's another hold strategic points for resources that allow you to purchase items that come in off screen. No bases but it's fast paced enough you don't miss them. ... Read Full Review
The game is really worth the money tho I got it for free - as an owner of the original game. For just 10 bucks you get a multiplayer of 40$-worth Order of War + 5 new modes/6 new maps/ optimized performance and tuned bal... Read Full Review