Would have to be Counter-Strike. There have been so many games that try to directly rival it and they just can't topple it. The game just has too much influence.
Considering all PC-exclusive games released, the following are considered the best based on critical reviews and user feedback:
Half Life by Valve in 1998, considered revolutionary during its time because of immersive gameplay, interesting balance of action, puzzle-solving, and storytelling Half Life 2 by Valve in 2004, acclaimed due to its realistic storytelling, character expressions, and movie-like graphics, similar to its predecessor Grand Theft Auto V by Rockstar North in 2015, providing players a gorgeous look into its setting, ultra-fast loading, and cool director mode Bioshock by Irrational Games and 2K Marin in 2007, applauded for its cinematic portrayals, compelling storyline and pacing, and over-all stunning atmosphere
