The Half-Life universe encompasses the first person shooter Half Life series, as well as the puzzle-based Portal series.
Half-life incorporates both cyberpunk and biopunk elements into the gameplay, setting and its sequel Half-life 2 features an alien force called the "Combine" who later transform treacherous humans into their "transhuman allies". They are led by "Synth" lords, a play on the idea of synthetic biology.
Gordon Freeman is the protagonist the half life series, an employee of Black Mesa and physics graduate. Later in the series he's hailed as saviour-like revolutionary against the occupying forces known as Combine.
Barney Calhoun is the protagonist in Blue Shift expansion pack and major character in Half Life 2 (with Half Life 2: Episode 1 as Main Character once more), formerly secrity guard for Black Mesa and survivior of Black mesa indicent, now Rebel spy in Half life 2 to save some citizens from abusing treatment of Combine.
Adrian Shephard is the protagonist in Opposing Force expansion pack, Its original goal is find Freeman and other scientists to kill them all until break off rest of army into survivial of his life.
The Portal series is take place in apparently post-apocalyptic and also more dirty postcyberpunk theme ruins of the Aperture Science underground research facility, which has been taken over by an out of control AI named GLaDOS.
Chell wakes up as a test subject within the abandoned complex, must discover what is going on whilst being subjected to a series of increasingly deadly test chambers. However the advanced portal gun technology allows her to innovatively defeat both the tests and the AI in the end.