Flashback: Doom

I've never played Doom, and I doubt I will for a long time unless I want nightmares, given I can find it. Doom is noted for being the #1 video game. Quite a title indeed, which should be enough to convince someone to buy the game if they were deciding if they should or should not. The game is set on Mars, and the character you control, which is actually meant to be you, is a space marine. One day, some UAC (Union Aerospace Corporation) experiments go wrong while on Mars, and quite a few things begin to happen. Computers on Phobos, one Mars' moons, malfunction, and Deimos, the other moon of Mars, disappears entirely, and "something fragging evil" pours out of the gateway of teleportation things. Reports go to the Martian marine and is sent to Phobos to investigate, where the player is left to guard the hanger with only a pistol, while the rest of the group proceeds inside. A few hours later, the player hears assorted garbled radio messages, gunfire, and screams, followed by silence: "Seems your buddies are dead".
Kinda creepy, right? Doom was so amazing that the first-person shooter was created. Without Doom, we may never have seen games like Halo, Call of Duty, or Half-Life.