26. "Half-Life"
Critic score: 96/100
User score: 9.0/10
Plot summary (from Metacritic): "Half-Life combines great storytelling in the tradition of Stephen King with intense action and advanced technology to create a frighteningly realistic world where players need to think smart to survive. Half-Life has won more than 50 Game of the Year awards from publications around the world, and was named 'Best PC Game Ever' in PC Gamer's November 1999 issue."