Half Life 2 Episode One
Episode One is the first in a planned trilogy of adventures Half-Life games.
Stepping into the hazard suit of Dr. Gordon Freeman, you face the immediate repercussions of your actions in City 17 and the Citadel.
Episode One is the first in a planned trilogy of adventures that extends the award-winning and best-selling Half-Life adventure. New Source Engine technology was introduced in Episode One to support advanced artificial intelligence, new levels of graphics and character interaction.