The Citadel, the gravity gun, the headcrab. Valve Corporation’s 2004 first-person shooter was a masterclass of game design that has endured, inspiring waves of video games, film and TV since.
We may earn a commission from links on this page. Remember Black Mesa, that really good fan-made remake of the original Half-Life built using the Half-Life 2 engine? Well, some of the devs behind ...