Eleven years ago, one of the benchmark titles in video game history launched: Half-Life 2. Releasing on November 16, 2004, the second entry in the Half-Life franchise once again starred protagonist Gordon Freeman as he faced off against the alien forces of the Combine.

The story begins with Gordon being woken by the entity known only as the G-Man to confront the aftermath of the events that took place at the Black Mesa Research Facility. The people at Black Mesa had inadvertently created an inter-dimensional rift that allowed alien life forms to come through to Earth, and though Gordon eliminated their leader, he ends up being forced to work for the G-Man. Gordon had been placed into stasis for nearly 20 years, and wakes to the horrors that now plague Earth.

Though Gordon is able to take down the alien Combine forces with help from a number of other human resistance members, at the end of the game he is captured and put back into stasis for an unknown purpose.

Not only was Half-Life 2 a critical and commercial hit, but it also marked the debut of developer Valve’s new game engine, called Source. The Source engine introduced new physics and rendering techniques that made the game stand out. Source has since been used for a number of other Valve titles, like Portal and Left 4 Dead, but it’s also been utilized by other developers on games like The Stanley Parable and Titanfall.

Half-Life 2 earned nearly 40 Game of the Year awards and is considered one of the greatest games ever made. It received two expansion packs, simply titled Episode One and Episode Two, though an official Half-Life 3 has yet to be even announced, more than a decade after the second game’s release.