I played the demo for the Orange Box. It was only the demo for Ep2 though.
It was awful. 10 minutes of talking, incredibly small amount of objects to use your gravity gun and Alex did more damage with her freaking pistol. I only had one fight too with about 3 zombies. I'm sure the rest of the game is better, much better, but this was a terrible demo.
Also, the Source engine is overrated.