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Half-Life 2 is a linear first-person shooter with light puzzle-solving elements and many setpieces, similar to its predecessor in concept.
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Gordon is soon brought into a resistance group, and makes a seemingly futile attempt to bring down the Combine and liberate the Earth. Meanwhile, Gordon Freeman, the man who was at the center of the events that took place shortly before the rise of the Combine, awakens from his stasis and is inserted into a train to City 17 by the mysterious G-man. Earth is turning into a grim, oppressive police state. An energy field prevents humans from procreating, and no new children are born.
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Wallace Breen, a human scientist, rules the city on behalf of his new masters. A Combine Citadel is erected in City 17, a town in Eastern Europe reminiscent of World War II ghettos.
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