[bloopernova]

The Marines also referenced sexual relations with "Arcturians" which might be human colonists or sentient aliens.

I really like your point about the Marines having fought/hunted/exterminated other "bugs". It casts their bravado in a different light. Even after seeing catastrophic damage from "acid for blood", the Marines are still very confident, which after beating other alien species, makes perfect sense. It's only when they get into the nest do they start getting scared.

[GMoromisato]

I love the scene where the marines go in for the first time. They start out well-disciplined, well-trained badass marines, but things start to go wrong one by one. First, they have to put away their rifles (too close to the fusion reactor), then they see movement on the motion-detector but can't see anything ("Maybe they don't show up in infrared"). Once Apone gets killed, the entire unit falls apart. They come out shell-shocked and demoralized.

It's a great scene.