List of creatures in the Half-Life series

Half-Life series
The series' logo, an orange lambda, is a prominent symbol throughout the series
Developer(s)	Valve Corporation (1998–present) Gearbox Software (1999–2001)
Publisher(s)	Sierra On-Line (1998–2003) Valve Corporation (2004–present)
Platforms	Windows OS X Linux Xbox Xbox 360 PlayStation 2 PlayStation 3 Shield Portable
Platform of origin	Windows
First release	Half-Life November 19, 1998
Latest release	Half-Life 2: Episode Two October 10, 2007

Half-Life (stylized HλLF-LIFE) is a series of first-person shooter games developed and published by Valve. The major installments feature protagonist Gordon Freeman, a theoretical physicist who battles an alien invasion. Two of these games, Half-Life and Half-Life 2, are full-length titles, while two more, Half-Life 2: Episode One and Half-Life 2: Episode Two, are shorter, episodic titles. A third episode, Half-Life 2: Episode Three, was scheduled for release by Christmas 2007, but is now described as vaporware.

The first game in the Portal series, set in the same universe as Half-Life, was released in 2007.

Half-Life, the first game in the series, takes place at the fictional Black Mesa Research Facility in New Mexico circa the turn of the 21st century. Gordon Freeman, a theoretical physicist, is involved in an experiment that accidentally creates a dimensional rift to a trans-dimensional world called Xen, causing extraterrestrial life to swarm the facility and kill the staff. As Freeman and the survivors try to flee, a military unit is brought in to contain the situation, including killing those that try to escape. Freeman ultimately makes his way to Xen and eliminates the alien "leader", the Nihilanth, but is confronted by the G-Man, who places Freeman into stasis.Half-Life: Opposing Force follows military soldier Adrian Shephard as he helps to quell another alien invasion within the Black Mesa facility. Within Half-Life: Blue Shift, Black Mesa security worker Barney Calhoun works to escape from the facility with Dr. Rosenberg and two other scientists.