Popular games built on game engine Source

The Stanley Parable Demonstration is supposedly the demo for The Stanley Parable, but has an original storyline and can be considered a short stand-alone game.

Underhell is a Source Engine game developed by the Underhell Team in collaboration with We Create Stuff. Underhell Chapter 1 requires ONLY Source SDK Base 2007 installed. No Source game is required. Underhell is split in 3 different zones. The first is "The House". Each new chapter will have its own version of The House with different puzzles, mysteries to discover, and diary pages of Jake's late wife to be found. The second is "The Dreams". With each new version of The House will come a set of dreams. They can be accessed by sleeping in the bed during the night. Dreams will give you bits of information about the story. They are very different from the rest of the game in both their narrative and gameplay, and focus mostly on exploration and solving puzzles. The Dreams are not bound by earthly rules and have a few twists to them that will challenge the player. The third is "The Chapters" where the main storyline of Underhell takes place. You can access a chapter from The House, and when it is completed, you are sent back to The House.

Sequel to the acclaimed Portal (2007), Portal 2 pits the protagonist of the original game, Chell, and her new robot friend, Wheatley, against more puzzles conceived by GLaDOS, an A.I. with the sole purpose of testing the Portal Gun's mechanics and taking revenge on Chell for the events of Portal. As a result of several interactions and revelations, Chell once again pushes to escape Aperture Science Labs.

1998. HALF-LIFE sends a shock through the game industry with its combination of pounding action and continuous, immersive storytelling. NOW. By taking the suspense, challenge and visceral charge of the original, and adding startling new realism and responsiveness, Half-Life 2 opens the door to a world where the player's presence affects everything around them, from the physical environment to the behaviors even the emotions of both friends and enemies.

The Orange Box is a bundle that includes five titles from Valve: Half-Life 2; Half-Life 2:Episode 1; Half-Life 2: Episode Two; Team Fortress 2, the sequel to the game that put class-based, multiplayer team warfare on the map; and Portal, the game that blends puzzles, first person action, and adventure gaming to produce an experience like no other.

The pessimistic, wisecracking, door-kicking zealot known as 'Bad Cop' is back. Command a small army of Combine synths and soldiers on a Northern campaign to capture Dr. Judith Mossman. Tread in the wake of Gordon Freeman at Nova Prospekt. Explore the mysterious 'Arbeit Communications' facility. Discover what lies beneath. Drive an APC through the arctic wastes. Confront the rebels on their doorstep and uncover a long-forgotten secret.

The second episodic sequel to one of the most influential first-person shooters of its time, Half-Life 2.

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.

Waking up in a seemingly empty laboratory, the player is made to complete various physics-based puzzle challenges through numerous test chambers in order to test out the new Aperture Science Handheld Portal Device, without an explanation as to how, why or by whom.

Team Fortress 2 Classic is a mod for Team Fortress 2 that recreates and expands upon the game's 2008-2009 era. The mod introduces the Civilian class from Team Fortress Classic, alongside pre-release weapons like the Nail Gun and Tranquilizer Gun. Players can participate in Four-Team matches with new GRN and YLW teams, and explore additional game modes including Domination and VIP Race. The mod features jump pads, flak cannons, and custom weapons that modify gameplay mechanics, while maintaining the original's art direction through enhanced textures, models, and restored toon-style shading. Team Fortress 2 Classic supports extensive modding capabilities and receives regular content updates from its development team.

A first- and third-person Western RPG based on the Vampire: The Masquerade tabletop RPG with a heavy emphasis on character building and role-playing, in which the player embodies a fledgling vampire under the guidance of vampire prince Sebastian LaCroix. The player must serve the prince while getting to know the various factions of vampires in Los Angeles and forming their own political views.

Fistful of Frags was born years ago as a Wild West themed modification for Source engine. It has been completely renewed for its Steam release, paying special attention to combat mechanics.

Portal Stories: Mel is a community made, free modification for Portal 2 based in the Portal universe. It tells the story of Mel, who meets a new personality core and faces an undiscovered threat to the Aperture facility.

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.

The Stanley Parable is a first-person exploration game which ponders questions related to player agency, narrative pacing, escapism through gaming, objective-driven game design, authorial intent, and the conflict of interest between players and game creators.

Titanfall 2 will deliver a crafted experience that explores the unique bond between man and machine. Playable offline, the single player campaign in Titanfall 2 will let fans step out onto the Frontier as a Militia rifleman with aspirations of becoming an elite Pilot. Stranded behind enemy lines and facing overwhelming odds, players must team up with a veteran Titan to uphold a mission they were never meant to carry out.

One of the most popular online action games of all time, Team Fortress 2 delivers constant free updates—new game modes, maps, equipment and, most importantly, hats. Nine distinct classes provide a broad range of tactical abilities and personalities, and lend themselves to a variety of player skills.

NEOTOKYO° is a multiplayer first person shooter that provides a visceral & realistic combat experience in a rich futuristic setting.

Left 4 Dead 2 is a cooperative first-person shooter video game, the sequel to Valve Corporation's Left 4 Dead. The Game builds upon cooperatively focused gameplay and Valve's proprietary Source engine, the same game engine used in the original Left 4 Dead. Set during the aftermath of an apocalyptic pandemic, Left 4 Dead 2 focuses on four new Survivors, fighting against hordes of the Infected, who develop severe psychosis and exhibit zombie-like tendencies. The Survivors must fight their way through five campaigns, interspersed with safe houses that act as checkpoints, with the goal of escape at each campaign's finale.

Portal: Revolution is a fan-made mod for Portal 2, which plays before the events of Portal 2 in the dead and decaying Aperture facility. Delve into a new story with original characters, spanning over 8 hours of gameplay and featuring over 40 new challenging test chambers that make use of new mechanics.

Counter-Strike: Global Offensive expands upon the team-based action gameplay that it pioneered when it was launched 19 years ago. CS: GO features new maps, characters, weapons, and game modes, and delivers updated versions of the classic CS content

Portal Reloaded is a free, community made modification for Portal 2. The mod builds on the concepts of the main game by allowing you to place a third portal, which enables traveling between two different timelines. Thinking in four dimensions is vital to solving 25 brand new mind-bending puzzles.

From Valve (the creators of Counter-Strike, Half-Life and more) comes Left 4 Dead, a co-op action horror game for the PC and Xbox 360 that casts up to four players in an epic struggle for survival against swarming zombie hordes and terrifying mutant monsters. Set in the immediate aftermath of the zombie apocalypse, L4D's survival co-op mode lets you blast a path through the infected in four unique “movies,” guiding your survivors across the rooftops of an abandoned metropolis, through rural ghost towns and pitch-black forests in your quest to escape a devastated Ground Zero crawling with infected enemies. Each "movie" is comprised of five large maps, and can be played by one to four human players, with an emphasis on team-based strategy and objectives. New technology dubbed "the AI Director" is used to generate a unique gameplay experience every time you play. The Director tailors the frequency and ferocity of the zombie attacks to your performance, putting you in the middle of a fast-paced, but not overwhelming, Hollywood horror movie. Addictive single player, co-op, and multiplayer action gameplay from the makers of Counter-Strike and Half-Life Versus Mode lets you compete four-on-four with friends, playing as a human trying to get rescued, or as a zombie boss monster that will stop at nothing to destroy them.

GoldenEye: Source is a total conversion mod developed using Valve's Source engine. GoldenEye: Source is a multiplayer remake of the 1997 Nintendo 64 video game GoldenEye 007, itself based on the James Bond film GoldenEye. The mod's development began in 2005, and remains in active development as of 2019.