Marty Stratton says it'll take around 18-22 hours to finish.
"It's definitely bigger than Doom 2016, longer," Stratton said. "I think the way we're challenging players will probably make it play a bit longer. My guess right now is it's in the 18-22 hour range on a pretty complete playthrough."
OMG OMG. thankyou id software. gone are the days when FPS campaign was over in 6 hour and focus on tacked on SP.
this is great news. Doom 2016 took 12 to 15 hour to finish. this more longer is more plus with having more variety