Immediately following the events in Doom, the player once again takes the role of the anonymous space marine who has proven too tough to be contained. After being teleported from Phobos, and subsequently fighting on Deimos which is suspended above Hell, the Marine finds himself back home on Earth, only to find that it too has fallen victim to the hellish invasion, leaving billions of people dead. The player progresses through 32 levels, which are divided into three chapters.rnrnIn the first chapter, the marine learns along the way that the remaining survivors of Earth's population are being held on Earth. The only means of escape is the space port which contains massive ships that can carry the remnants of Earth's population into space. The demons, predicting this avenue of escape, have placed a force field over the space port so those ships cannot land or leave. The marine must battle his way through the infested space port and deactivate the force field. Once humanity is finally evacuated from the ravaged, infested planet, the marine is the only human left on Earth.