Black Mesa research facility, an ultra-secret laboratory under government contract, conducting top-secret and extremely volatile experiments with stuff you're not supposed to know about. You are Gordon Freeman, a Black Mesa employee. And this morning, as usual, you pit your way to the research facility for a run-of-the-mill experiment.

Only this morning's experiment is not quite as ordinary as you thought. Odd things begin to happen as you make your way to one of the Black Mesa test chambers. Even weirder things happen when you start to move the Test Sample towards the antimass-spectrometer.

And you ain't seen nothing yet.

Yes indeed, the experiment went wrong. And more importantly, someone wants to keep this hush-hush operation a secret. And you know what that means, you'll have to fight your way through to the top of the Black Mesa complex. Bizarre, alien lifeforms will make your life harder. Trained marine squad will make it even harder. And when you face your ultimate challenge, you'll see just how much being a government employee really does suck.
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