Why Half Life?

[Preator]

What's Decay mean, ey?

Err... To decompose or to rot, the gradual decrease in somethings health, excellence and prosperity >.>
both make perfect sense in Half Life, i doubt the names were just chosen as a title, theres more ideas running behind them

 

[Satans_Offspring]

Lol, dont you ever go on Wikipedia?

Read this: http://en.wikipedia.org/wiki/Biological_half-life