Half-Life series

'Half-Life series' may refer to any combination of associated products. The core of the Half-Life series concerns the adventures of Gordon Freeman, a scientist working for a private research facility who is forced in the face of multiple alien offensives to become a mercenary for a mysterious entity known only as the G-Man. These products include:

• Half-Life (PC, Playstation 2)
• Half-Life 2 (PC, XBox, XBox 360, Playstation 3)
• Half-Life 2: Episode One (PC, XBox 360, Playstation 3)
• Half-Life 2: Episode Two (PC, XBox 360, Playstation 3)
• Half-Life 2: Episode Three (PC, XBox 360, Playstation 3)

A series of expansion packs were developed by third party developer Gearbox Software. These each star their own protagonist(s) but revisit the Black Mesa facility seen in Gordon Freeman's Half-Life adventure:

• Half-Life: Opposing Force (PC)
• Half-Life: Blue Shift (PC)
• Half-Life: Decay (Playstation 2)

The Half-Life name is also carried by a number of minor products of varying canonical value

• Half-Life: Day One (PC)
• Half-Life: Uplink (PC, Playstation 2)
• Half-Life: Lost Coast (PC)

Finally, there is Portal, A first person puzzle game which is set at a point in the Half-Life story, though it doesn't carry the Half-Life label.