Final Doom: The Plutonia Experiment PC Gameplay

The Plutonia Experiment is an IWAD released on June 17, 1996, which forms one half of Final Doom (the other half being TNT: Evilution). The name comes from the word Plutonian, meaning something associated with the Underworld/Hell.
Final Doom consists of two parts: Evilution and the Plutonia Experiment. In the first, your task is to avenge your fallen comrades, in the second, you are a marine charged with the task of closing one of the gates to Hell.
Game consists of two parts: Evilution and the Plutonia Experiment. In the first, you are the lone human survivor of a devastating raid on a Jovian moon base by the forces of Hell. Your task is to avenge your fallen comrades. In the second, you are a marine charged with the task of closing one of the gates to Hell before it is used by Hell's minions to launch another invasion of Earth.
—James Brazel
Two new, 32-level Doom II episodes. Evilution: Far from earth, the UAC recommenced their experiments on on of the moons of Jupiter. A spaceship, mistaken for a supply vexxel on radar, hovered above the base. Hideous demons poured out, blanketing the base with death. All your comrades were quickly slaughtered or zombified. This time, it's not about survival. It's about revenge. The Plutonia Experiment: Every effort has been made by the nation's top scientists to close the seven interdimensional Gates of Hell, but one portal remains open. Alone, you must infiltrate the ravaged complex, defeat the demon Gatekeeper and seal the last Hell-hole before the undead are prepared to, once again, take over the world.