While some claim that the basic shape was based on a submarine,the design has most often been described as a 'gun in space' due to the elongated form resembling the pulse rifles used in the movie—with Syd Mead agreeing that (in addition to Cameron's preferences) this was one of the reasons for the switch from the spherical form.[7] Other film analysts have remarked on how the opening shot of the ship as something sinister and weaponlike presages Ripley's transformation during the movie into a warrior figure, akin to the hardened Marines the Sulaco already carries
https://www.youtube.com/watch?v=9CS7j5I6aOc