Half-Life 2: Episode One is an Action-Adventure, First-person Shooter (FPS) and Single-player video game developed and published by Valve Corporation. It is the first title in the series of episodes and serves as the sequel to Half-life 2, released in 2004. The story of the game takes place right after the event of Half-life 2 and set in War-Torn City 17. The game follows the protagonist, a scientist named as Gordon Freeman and his assistance Alyx Vance as they fight against alien civilization known as the Combine to rescue the humanity. The game starts with the protagonist, who wakes up out the base of the enemy operation, the Citadel. During the mission, the player must traverse with his companion to explore the city from the first-person perspective. As the game ends, both characters are caught in a series accident, and their destiny are unearthed in the sequel called Episode 2. There are a variety of levels, and each level needs a completion of individual objectives to progress through the game. The player assumes the role of the protagonist, and he must complete several missions at any cost to save the humanity. Try it out, and you’ll love it.