No, they were individuals, killed in the climactic battle, the ridged head aliens were yes ALL killed in part of the climax, but they were first a group, and second killed throughout the film. If you don't like how the topic is set up, leave. There is no reason to stick around and complain about it.
Also, that Alien is not the Giger Alien, It's from AVPR, but I am sure you knew that.