Throughout the course of the game, the player accesses new weapons and ammunition that are used to defend the character from enemy forces. A heads-up display appears on the screen to display the character's health, energy, and ammunition. Episode One integrates tutorial-like tasks into the story to familiarize the player with new gameplay mechanics without breaking immersion. The gameplay is broken up between combat-oriented challenges and physics-based puzzles. In Episode One players make their way through a linear series of levels and encounter various enemies and allies. Episode One received a generally positive critical reaction, and the co-operative aspects of the gameplay received particular praise but its short length was criticized. Episode One is available as part of a bundle package known as The Orange Box, which also includes Half-Life 2, Episode Two, Team Fortress 2, and Portal. Valve views episodes One through Three as tantamount to a standalone release. As the game comes to an end, Gordon and Alyx are caught in a major accident, and both of their fates are revealed in the sequel, Episode Two. During the course of the game, Gordon travels with Alyx as they attempt to evacuate the city. When the story begins, Gordon wakes up outside the enemy's base of operations, the Citadel, after being left unconscious from the concluding events of Half-Life 2. Episode One follows scientist Gordon Freeman and his companion Alyx Vance as they fight in humanity's continuing struggle against the transhuman race known as the Combine.

The game's events take place immediately after those in Half-Life 2, in and around war-torn City 17. The game debuted new lighting and animation technologies, as well as AI sidekick enhancements. Similar to Half-Life 2, Episode One also uses the Source game engine.

Originally called Half-Life 2: Aftermath, the game was later renamed to Episode One after Valve became confident in using an episodic structure for the game.

It was developed by Valve Corporation and released on June 1, 2006. Half-Life 2: Episode One is a first-person shooter video game, the first in a series of episodes that serve as the sequel for the 2004 Half-Life 2.

Half life 2 episode one