The average score for Halo Wars is 82% as can be seen here:
http://www.metacritic.com/games/platform...
Halo Wars is still a good game though. If you're a big Halo fan like me you would be pleased be to see that the graphics, sound, and story are very much like the Halo trilogy. The cut scenes are very well done, the story is interesting and everything looks, moves and sounds like a Halo game except there is one big problem.
The problem is the actual gameplay and gameplay is the most important part of a game. This is a strategy game and the problem is that to finish the game you don't need to use any starategy whatsoever. You can just blast through the entire game without putting any though into what you're doing which isn't a lot of fun, making the game very simple.
So it's a pretty good game, but really not worth your money.