DOOM: Legions of Hell mod for Wolfenstein 3D

May 24, 2177 A.D.

You are on a transport vessel heading towards Mars. You have been in the Marines for 15 years, and served the planet loyally. You were just promoted and your first mission was a distress call from Mars. Every one of your friends has gone to Mars, and said the distress calls were basically routine. By that, you thought there was nothing to worry about.
The ship entered the atmosphere and then landed at one of the ports. A sandstorm was just picking up, so you were losing visibility as you walked into the giant facility. Inside was like any building on Earth. You dropped your luggage off and followed your group. They all went into the General's office, the man who was controlling the military activity on Mars.
He gave you the low-down of what they needed to do. An accident had happened in one of the lower engineering platforms. It wasn't anything serious, but it was causing repercussions that cut half of the building's output. You had to go to a remote part of the facility and help some scientists get back on track. It was a child's job. This kind of order didn't seem like a serious job of a higher class marine, but not to get into trouble you followed the orders.
When you arrived in the lower shafts, you heard a noise. It sounded like the building collapsing, but you decided to ignore it. Then you came to the lab where a mess of scientists were supposed to be. No one around. It seemed kind of strange that there were no scientists anywhere. You looked around to see if they had just left, everything was still running, like they had left a matter of minutes ago.
You glanced at a couple papers that they were working on, it said "Bio-Force Gun Project." There were a few pictures of the weapon. It was supposed to be their greatest work ever. You thought to yourself, "that's a nice gun, wouldn't mind having one of those."
As you set the papers back on the desk someone jumped you and began to scratch and pull at you. You flipped him over your back and pointed your shotgun at him. It was one of your squad, he looked as though his face was burned and he was foaming blood and saliva at the mouth. You shot him because it didn't look like he was himself. You looked up and there was blood everywhere. It was shocking as hell, you ran to the next room to find a mutant-looking creature there.
Something happened, but you do not know what. You tried to call for a reply on the radio, but no one answered back. Static filled the speaker, no voices. Then a loud shriek cried out from the next room. Your shotgun was out of ammo, so you left it behind and pulled out a sidearm. There was something definitely going on, and it wasn't good. This had to be stopped before it got worse.