Doom official Twitter post information about Doom single-player campaign. When a follower asked that, how long the single-player campaign would be, he got this reply by Doom official page “The difficulty level plays a factor, but folks playing at the office average 13+ hours in the campaign”.
.@Unreal389 The difficulty level plays a factor, but folks playing at the office average 13+ hours in the campaign
— DOOM (@DOOM) February 11, 2016
With 17 mission, Doom Single-Player may trend out be long enough, although isn’t really a single-player game. But we will all find out on May 13, when Doom will release on PC, Xbox One and PS4.