^Err, no. You're not forced to move, you're not forced to shoot. The game won't progress, but you're actually not forced to take any actions. They don't happen without your will. When you enter a new room you're not forced to look into a direction, even when characters try to call for your attention. If Gordon spoke to a character when he saw him/her, then for the first time you'd be forced into something.
When I say that you have a fully immersive experience I'm not speaking of having complete freedom, because I never said that the experience in which the immersion happens is that of a free world. No game guarantees that, all games offer immersion into a smaller world with definite rules. I speak of a game that sets those rules very clearly and always plays by them, so that once you know them you will never be yanked out of the game world by their violation.
And frankly, they have some pretty good writers. Some of them are experienced game writers, at least one -Marc Laidlaw- is a writer of SF and horror novels that only later started working with Valve.
The characterizations, expressiveness and dialogs for all other characters are great, so I have little doubt that if they wanted they would have managed to explicitely build a character for Gordon and to write his lines accordingly.
It was not a cop-out, it was a conscious design decision that was probably actually harder to follow through.







