Power up your environmental suit and plunge through level after level of increasingly difficult and creepy challenges, rescuing your fellow scientists and ultimately clearing out the whole complex--if you're lucky. Game play is smooth and simple, after the obligatory false starts and botched maneuvers common to learning every new game. Persistence pays off, though: Half-Life rewards tenacity with increasing power and understanding of the virtual world.

Play on a network and cooperate or compete with folks across the world or in the next cubicle. For those who've mastered the intricacies of Half-Life , the Game of the Year Edition includes Worldcraft 2.0, which the designers used to build every detail of the base. Make your own levels and snicker at other players' pathetic attempts to evade your deathtraps. It's easy to see why Half-Life won Game of the Year from dozens of publications; try it and see for yourself--if you're not too squeamish. --Rob Lightner