For 10 points, identify this
A piece of fan fiction about this game is subtitled "Repercussions of Evil" and revolves around John Stalvern. Spider Masterminds and Revenants were missing from its N64 version, though that game did contain the Laser of the Unmaker. Its first sequel added the Megasphere and ended when the player killed the Icon of Sin by shooting rockets into its brain; that sequel was subtitled Hell on Earth. Its shareware version consisted of the episode Knee Deep in the Dead, which began with the vanishing of Deimos and the arrival of demons on Phobos. For 10 points, identify this id Software FPS, in which the BFG 9000 is among the weapons used by the player, a Space Marine.
A piece of fan fiction about this game is subtitled "Repercussions of Evil" and revolves around John Stalvern.
DOOM [accept Doom 64 or Doom II on the relevant clues]