At the risk of this have been discussed already....

Now, the following is not a Spoiler, as it was taken from the
HL2-Episode 1 web site: http://ep1.half-life2.com/story.php

"Consciousness returns. Gordon and Alyx discover they've somehow escaped
both the reactor explosion and the G-Man's malevolent grasp. Before they
can ponder their miraculous survival, the crippled Citadel lurches back
to life just long enough to initiate a self-destruct sequence. With Alyx
at his side, Gordon must flee a city in chaos before the Citadel's final
detonation turns City 17 into a toxic, mutant-infested crater."

But, just for the sake of argument, one could say that the above might
be just the description of Episode 1, isn't it?

Btw, was it out next month?

J.