Basically, there's no plot restriction about this story, except that the whole overarching plot is about survival horror, set in space. There's also minimal background setting supplied at the beginning, and the background setting is expected to be uncovered little by little as the story progress along the choice. So if any branching story suddenly has a different background setting than another choice, as long as it's on the track with the previous storyline, this is reasonable to happens. So get your creative juice flowing!