Alien 3 (1992)

Continuity mistake: Any shot of the alien which isn't made using a guy in a suit has a green glow around the alien's body but any guy-in-a-suit shots do NOT have a green glow.

THGhost

Andrews: We're 25 prisoners in this facility. All double-Y chromos. All thieves, rapists, murderers, child-molesters. All scum. Just because they have taken on religion doesn't make them any less dangerous. I try not to offend their convictions. I don't want to upset the order. I don't want ripples in the water. And I don't want a woman walking around, giving them ideas.
Ripley: I see. For my own personal safety.
Andrews: Exactly.

Trivia: The film had a notoriously troubled production, with several writers and directors dropping out of the project during development. With a looming release date, sets were built and a crew was assembled before a script was even settled on, and the final draft had to be written around the sets that had already been built. David Fincher, then a popular music video and commercial director, was chosen to helm the film, but he had nonstop creative difficulties with the producers and studios. He has since gone on to disown the film, as he feels it isn't reflective of his vision.

Question: In the scene where Ripley is describing the new Alien, she says it 'moves different to the other ones'. I could never get a good enough look at the alien to understand what she meant. What did she mean and why does it move differently?