Well, it's more a sequel to Alien 3 in terms of it's placement in chronology. Spiritually it's a sequel to Aliens, but... Well, questions like "How the eggs got on the Sulaco" may have been ignored entirely, or be only vaguely dealt with. I don't know yet, I have not yet received my copy, but what I've seen in the playthroughs seems to indicate they probably don't go into detail.