While originally announced as a pre-order bonus, the downloadable content will also be released at a later date.
"It's genuinely been great to see the reaction to The Crew Expendable and Last Survivor pre-order bonus content we announced yesterday and how excited you all are to re-experience those classic scenes from the original movie with our Alien. It's been absolutely amazing for us at the studio," wrote the studio's community manager.
"However, some of you have been asking if the two pieces of content are only available through pre-order or if we'll be releasing them at a later date as well. So, I can confirm today that we do plan to release both Crew Expendable and Last Survivor at a later date and we'll have more details for you guys on that shortly."
Alien: Isolation, due to release on Oct. 7, is set 15 years after the events of the original film. It is the story of Ellen Ripley's daughter, Amanda, who is investigating the disappearance of her mother. Alien: Isolation's story takes place on the space station Sevastopol.
Alien: Isolation will launch on PlayStation 3, PlayStation 4, Windows PC, Xbox 360 and Xbox One. For more see Polygon's preview of the game from E3 2014.