Half Life offers a brilliant campaign, and in my opinion, is better than it's successor; Half Life 2.
Half Life's story is a great feature about it, You are put in the hands of Dr. Freeman, a scientist who has been transfered to the Black Measa Research facility, you arrive late and are assigned to an experiment, then suddenly it horribly goes wrong, by now mutant aliens are being transported into the facility, and scientists and security guards are being slaughtered, and they decide to send in the commandos to evacuate everyone, but they have their own ideas.
Half Life offers revolutionary controls and graphics for its time, fun weapons, brilliant story and a Horror atmosphere.
This sci-fi/horror First Person Shooter could be the best Shooter. It's your decision, but even after years of its release, you should defiantly buy this game.
9.2/10