Phobos Mission Control

Phobos Mission Control or E1M4b is a single-level PWAD for Doom designed by John Romero and released on April 26, 2016. The wad was made to be a teaser for Romero's upcoming shooter, Blackroom. The level occupies the E1M4 slot and contains 153 monsters and 6 secrets.

Story
''With the Toxin Refinery in the rear-view, you make your way to Phobos Mission Control where the computers crunching the data from the Phobos Anomaly are located. You need to use them to gain access to the Phobos Lab, but remember hearing that the computers were tied into all areas of the installation and that you never knew when the environment around you would change. You need to keep your eyes alert to all movement - this place is not what it seems...''

Walkthrough

 * Letters in italics refer to marked spots on the map. Sector numbers in boldface are secrets which count toward the end-of-level tally.

Development
Romero chose to replace E1M4 because it was one of two levels in Episode 1 not designed by him, but by Tom Hall, and he wanted to create an episode consisting only of his own work.

Like E1M8b, E1M4b was built with Doom Builder 2 and took Romero two weeks to finish. Linguica, Matthias Worch, and Ian Dunbar contributed to the project in the form of playtesting.