Half-Life: Blue Shift

Half-Life is a 1998 first-person shooter (FPS) game developed by Valve Corporation and published by Sierra Studios for Windows. It was Valve's debut product and the first game in the Half-Life series. The player assumes the role of Gordon Freeman, a theoretical physicist who must escape from the Black Mesa Research Facility after it is overrun by aliens following a disastrous scientific experiment. Its gameplay consists of diverse combat, exploration and puzzles.

Half-Life: Alyx is Valve’s VR return to the Half-Life series. It’s the story of an impossible fight against a vicious alien race known as the Combine, set between the events of Half-Life and Half-Life 2. Alyx Vance and her father Eli mount an early resistance to the Combine's brutal occupation of Earth.

Half-Life 2: Episode Two is a first-person shooter set in the aftermath of the Citadel's destruction. Players control Gordon Freeman as he and Alyx Vance travel through forests and underground tunnels toward a resistance base, facing Combine forces and new enemy types along the way. The game emphasizes vehicle-based combat sequences alongside the series' physics-driven puzzles and gunplay.

Half-Life 2: Episode One is the first of a planned trilogy of expansion packs/episodes for the 2004 first-person shooter game, Half-Life 2. The episode takes place immediately after the end of Half-Life 2, in the war-torn setting of City 17. The player is forced to deal with the effects of their actions during the main game. The episode is a stand-alone game; while a continuation of Half-Life 2, it does not require the original game to be installed or registered to a user's Steam account to play. It takes advantage of several major upgrades to the Source engine since the release of Half-Life 2, primarily its high dynamic range rendering capabilities and the upgraded facial animation system. Episode One was released together with Half-Life Deathmatch: Source, a port of the original Half-Life's multiplayer, which doubles as Episode One's multiplayer component. The retail copies of Episode One also come with Half-Life 2 Deathmatch for those who have not previously purchased the later title.

Half-Life: Alyx is Valve’s VR return to the Half-Life series. It’s the story of an impossible fight against a vicious alien race known as the Combine, set between the events of Half-Life and Half-Life 2. Alyx Vance and her father Eli mount an early resistance to the Combine's brutal occupation of Earth.

Black Mesa is a re-envisioning of Valve Software's classic science fiction first person shooter, Half-Life. Powered by Source Engine, You will re-visit the inaugural role of Gordon Freeman and his memorable journey through the Black Mesa Research Facility. Expect detailed environments to explore, a huge cast of characters and experimental weaponry. All-new music, voice acting, choreography and added dialogue give way to a more expansive and immersive experience than ever before.

Black Mesa: Definitive Edition includes performance improvements with a higher frame rate in some levels and visual upgrades, as well as all new and expanded Xen levels.