The Evil Within, the upcoming horror title from Shinji Mikami, should have an approximate running length of roughly 15 to 20 hours. That's according to Mikami himself, who wrote on Twitter: "We expect The Evil Within campaign to last 15-20 hours depending on play style and difficulty mode."
On top of that there's also the recently announced Season Pass for the game, which includes an additional two-part story campaign. The Evil Within is heading to Xbox One, Xbox 360, PS3, PS4 and PC on October 17.