The Creative Assembly's Gary Napper has confirmed in a recent interview that Alien: Isolation has a running time of around 15 hours, although the lead game designer concedes that a stealthy player can get through it in less time.
"The game's actually about 15 hours long because we've got so much to do with the narrative and all the different mechanics of the alien," Napper told The Angry Joe Show.
"On top of that we have the other threats about the station, we have a big long story that folds out. Also it's a bit like a Metroidvania game where you have a linear story you go through but you can also go back and explore areas you've been to. You can go back to areas and find new things, explore and open up new areas. There's a lot to do in the world.
"The difficult thing is nailing a time because people can play for absolutely ages without even seeing the alien because they're being really careful and really stealthy, they've done nothing to call him down or there have been no explosions that he has come to investigate. Those people can get through it fairly quickly."
Alien: Isolation is set to launch on PC, PS3, PS4, Xbox One and Xbox 360 on October 7.