Races playable at the blizzcon demo?

ive said this in a few other posts, but maybe after blizz was working on zerg for a while, they hit a wall with concepts for units, balancing issues, etc. and had to go back to square one, or just set them back a lot.

 

I heard somewhere in an interview in may that "something big is going down for the zerg." The guywould just not shut up about the zerg. So I am almost positive if they aren't playable that there will be stuff revealed about them.

 

Well so as of today nothing about the Zerg.
There is multiplayer gaming between Terran and Protoss. The game plays very much like SC1, but a few new units and of course awesome new eye candy. The environments are so gorgeous its kind of distracting but nice.
Oh and during the Q&A about the single player campaigns there was talk of ancient artifacts from another race... So not a playable "other race" but one that might make for an outside enemy like we've seen in past Blizzard games. The new single player campaigns are going to be “free form†and sound awesome.

 

the ending and major events will be fixed, but you can choose the missions to get there

 

They compared it to a foot ball shape campaign. Specific beginning specific end with a wide range in between where “anything†can happen.