Valve gave the Half-Life 2 team 40 million dollars and no deadline in 1999, along with Gabe Newell’s expectation that anything short of the best PC game of all time would bum everyone out. This episode follows the decision to build the Source engine at the same time as the game, the move from Black Mesa to Viktor Antonov’s Eastern European City 17, and Ken Birdwell’s study of psychologist Paul Ekman’s facial coding to give characters like Alyx and Eli Vance real emotion.

The hosts explain how the Havok physics integration and an internal Zombie Basketball test birthed the gravity gun, then walk through the 2003 E3 promise of a September release, Newell’s silent Alcatraz appearance, and the September 19, 2003 theft of the source code by German hacker Axel Gembe, including the FBI-coordinated fake job interview. They finish with the ruthless cuts after the first full playthrough, the November 16, 2004 launch that forced Steam onto millions of PCs, the Vivendi cyber cafe lawsuit, 39 Game of the Year awards, Garry’s Mod, a texture traced to a medical textbook, and a 20th anniversary peak of over 64,000 concurrent players.

• Building the Source engine while building the game: the custom camera lens problem
• How Ekman’s facial action coding turned NPCs from signposts into people worth protecting
• The gravity gun and why physics puzzles rewired player psychology
• The 2003 source code leak, the million-dollar-a-month delay, and the sting that never happened
• Forcing Steam on a dial-up world and winning the legal fight that defined digital distribution