Gargantua. image - EvilStar: Beyond Doom mod for Doom II

During the invasion of hell, the demons' presence drastically altered our planet. Many areas on the planet are now uninhabitable due to the fact that they resemble hell more than earth now. After the invasion was stopped, what remains of the UAC decided that the only hope to save the planet was to build a time machine to go back in time and warn the Phobos labs about what was about to begin. The day of the experiment has finally come, you, Flynn Taggart, the marine who saved earth and humanity, are just a security guard to make sure that nothing goes wrong during the time travel...