The first part was so grand! I felt like I was in George Orwell's 1984, I kept looking for the Minsitry of Truth. I half expected the guy on the video screens to be "Big Brother". It was chilling, it was a great setup for what was a great game.
However, it left me in shock because, after playing through 12 hard heart pounding levels of intense action, the ending was horrible. I won't say the ending was the worst I'd ever seen, but it did feel that way because the rest of the game left me with such high expectations.
The ending was so bad... it sapped my will to actually replay it. Oh mind you, I love going through such levels as "Ravenholm" and the highway, but I don't think I'll go all the way through again, the ending was just *that bad*.
The only hope I have is that Valve is planning to go somewhere really cool with this. I think they are, but we'll have to wait and see.