Storyline:
Quake 1: Shoot stuff and beat a chapter and see what happens
Quake 2: Some strogg stuff took over the word so you have to shoot stuff
Quake 3: Shoot friends and strangers on the internet
Quake 4: Some strogg stuff took over the world so you have to shoot stuff
With a game like quake I don't really care about the story. Especially quake 1, where I shoot everything I see without a second thought.