The new Alien film “Alien: Romulus” has drawn mixed responses from critics for its reimagining of the classic sci-fi/horror franchise. While praised for its reliance on practical effects over CGI, the movie has sparked debate with two major creative choices.

One point of discussion centers around the use of CGI to recreate the late actor Ian Holm’s likeness for his character Rook, an android that first appeared in the 1979 original film. Director Fede Alvarez explained that while Rook’s body was played by an animatronic, digital technology was employed to generate Holm’s facial expressions based on a new actor’s performance. This has split opinions, with some arguing it detracts from the film’s mainly practical effects approach.

A second controversial element involves including the human-alien hybrid creature known as “The Offspring” in the climactic scene. Alvarez said the studio initially had doubts but he pushed for including it,...