Half-Life 2 continues the story of Gordon Freeman, the scientist-turned-marine who managed to escape from the Black Mesa Research Facility in Half-Life. In Half-Life 2, Gordon has accepted the G-Man's "offer" and become a government agent on Earth. However, the Xen aliens, Combine soldiers, headcrabs, "ant lions," and other enemies threaten everything.
Gordon begins his quest in City 17 and, with the help of Eli and Alyx Vance, begins to unravel the mysteries behind the rapid changes on Earth. Freeman also encounters gigantic spider-like monstrosities that tower over buildings, impale humans on sharp spindly legs, and emit devastating blasts from their bodies -- "striders."