Ep. negative 4: Half-Life. Ep. negative 3: Opposing Force (ultimately, non-canon) Ep. negative 2: Blue Shift (originally slated to be included with the DC version of HL, so potentially canon. Fan-game Azure Sheep has the same storyline but is a better game) Ep. negative 1: Decay (verified official canon and developed by Valve themselves)
Half-Life is a 1998 first-person shooter 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 scientist who must escape the Black Mesa Research Facility after it is invaded by aliens following a disastrous scientific experiment. The gameplay
Publisher: Valve Software. Release Date: 10.10.07. Engine: Source. Protagonist: Dr. Gordon Freeman. Settings: City 17’s outskirts, somewhere in Eastern Europe (Bulgaria, Romania or Ukraine). Continuing the plot of Half-Life 2 and Episode One, Episode Two consists of seven chapters telling the story of Gordon Freeman and Alyx Vance's journey
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