Valve president Gabe Newell set his team the goal of redefining the FPS genre, focusing on advanced physics systems and non-player characters. Development lasted five years and cost US$40 million. The game was created using Valve's Source engine, which was developed at the same time. Set roughly twenty years after the first game, players control Gordon Freeman as he joins a resistance movement to liberate the Earth from the control of an alien empire called the Combine. Like the original Half-Life (1998), it combines shooting, puzzles, and storytelling, and adds features such as vehicles and physics-based gameplay. Half-Life 2 is a 2004 first-person shooter game developed and published by Valve.
