Half-Life 2

Following the period of instability caused by the events described in Half-Life, an interdimensional organization known as the Combine invades the Earth, defeating the human forces in the Seven Hour War. A Combine Citadel is erected in City 17, a town in Eastern Europe reminiscent of World War II ghettos. Dr. Wallace Breen, a human scientist, rules the city on behalf of his new masters. An energy field prevents humans from procreating, and no new children are born. Earth is turning into a grim, oppressive police state.

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. Gordon is soon brought into a resistance group and makes a seemingly futile attempt to bring down the Combine and liberate the Earth.

Half-Life 2 is a linear first-person shooter with light puzzle-solving elements and many setpieces, similar to its predecessor in concept. The player guides Gordon Freeman through City 17 and the wilderness that surrounds it. On his way, he'll encounter a few friendly characters, but also fight dangerous foes. The game features a realistic physics system: Gordon can pick up objects and toss them freely, and many of the puzzles are physics-based - for example, at one point the player has to weigh down a seesaw with bricks at one end to turn it into a ramp.