Half Life Soundtrack About This Game Named Game of the Year by over publications, Valve’s debut title blends action and adventure with award winning technology to create a frighteningly realistic world where players must think to survive. Also .A VR Return to Half Life. Set between Half Life and Half Life , Alyx Vance and her father Eli mount an early resistance to the Combine’s brutal occupation of Earth..The Half Life saga is the story of Gordon Freeman, a physicist who finds himself at the center of resistance to an alien invasion that threatens the future of humanity. From Valve’s debut game onward, the series has been at the forefront of immersive action and storytelling..Half life, in radioactivity, the interval of time required for one half of the atomic nuclei of a radioactive sample to decay change spontaneously into other nuclear species by emitting particles and energy , or, equivalently, the time interval required for the number of disintegrations per.Half life [haf lf] the time required for the decay of half of a sample of particles of a radionuclide or elementary particle see also radioactivity. Symbol t or T . half life haf’lf , The period in which the radioactivity or number of atoms of a radioactive substance decreases by half similarly applied to any substance, such as a .