Over on the official Halo War forums, the game's dev team is reporting that they were able to put together a fairly polished version of Halo Wars for a "bunch of Microsoft Games Studio big wigs" to play in a recent visit. Said big wigs included Shane Kim, the studio's head.

The build included new UI work by Ensemble Studios folks and left the visitors quite impressed. It sounds like it's got to be fairly far along:

With this latest build of the game, everyone at Ensemble Studios was invited to join in on an afternoon of multiplayer Halo Wars! I had a win and two losses, but generally felt like I was starting to shed my newb shoes.

So the game is very playable, it sounds like. Brian Crecente

Halo Wars Update [Forums Halo Wars]