By taking the suspense, challenge and visceral charge of the original, adding startling new realism and responsiveness, Half-Life 2 opens the door to a world where the player's presence affects everything around him, from the physical environment to the behaviours - even the emotions - of both friends and enemies. The player again picks up the crowbar of research scientist Gordon Freeman, who finds himself on an alien-infested Earth being picked to the bone, its resources depleted, its populace dwindling. Freeman is thrust into the unenviable role of rescuing the world from the wrong he unleashed back at Black Mesa. And a lot of people - people he cares about - are counting on him.