DOOM - Exit Elevator

So when you complete the first section of the first level of DOOM (2016) you take an elevator up and after a short story sequence the title cards play. After they end, you walk out onto the surface of mars... if you happen to look behind you at where you came from, for a few seconds you'll see this secret entrance lower back into the ground. 

Official Website: doom.com/en-us/

© id Software, LLC, A Zenimax Media Company