When used as noun rather than verb, and especially with that capitalisation, burns a particular image with gamers who grew into their addiction through the 90s.
Memories that might have you committed by the state, perhaps exorcised by the church, definitely lambasted by the tabloid press. In '93, DOOM was the video game nasty, adrenaline-fuelled slaughter egged on by a pumping industrial score that tore the midi files a new one. Shotgun blasts eviscerating zombified soldiers, chainsaws turning hellhounds to mulch. Charging through dank labyrinth mazes and army bases searching for door keys and secret rooms.
It was the template for every first-person shooter to come. But it did more than birth a genre.
DOOM paved the way for the concept of system-linked death-matches. Of hunting down players divided by networks and countries but only a well-aimed RPG rocket away from death. That the game was banned in offices worldwide due to huge drops in productivity has been retold so many times it's entering into myth.
My defining moment with DOOM is actually two: the latter, coming eleven years after my first experience with the title, was in itself a defining moment, but more importantly re-enforced the first, and how different my DOOM experience was from others.
I celebrated Christmas of 1995 locked in my bedroom with PSOne controller clutched in sweating hands and a notepad and pencil by my feet, scrawling down level codes as I went, the only respite I had from being scared shitless and wide-eyed addicted in equal measure. I was some six months shy of the BBFC 15 Rating emblazoned on the box.
The sprite work and the gore-filled explosions look rudimentary today, but it was a horrifying delicacy at the time, aided by still hands-down the best audio for weapon discharges; every FPS worth its salt copied the raw power of the shotgun, but none have matched it.
To clarify my first defining moment I need to explain the second. Eleven years later I came across DOOM again by way of the XBLA re-release. From the very first level Hangar I realised something was vastly different, and a quick Youtube check confirmed that the music in this version was an exact copy of the PC original.
Music lends a huge amount to creating atmosphere in video-games: tension, suspense, thrills, action. The midi tracks of the 80s and 90s are more memorable than today's orchestrated counterparts due in part to their innate simplicity; the same looped rhythm cycled through numerous times per level engrains on the brain. You can whistle Mario, but you'd have trouble completing a run through of a Mass Effect theme.
Compare a run-through of the Hanger on PC against the same level on PSOne. Even with the player being a hotshot pro in the second, the background music gives the experience, and the entire game, an entirely different feel.
The switch from midi rock to ambient, sinister tones completely inverts the player's reaction to the level. Well, it certainly did with me. My DOOM experience was spent nudging round corners and nervously ducking into rooms, panic firing at every noise. Seemingly I had spent eleven years locked in a sadomasochist's dungeon desperately trying to survive. Everyone else was at a Rammstein concert indiscriminately punching strangers.
I wouldn't change that original experience at all. For one the low-level vibe fitted in nicely with the edgy industrial-style tracks that I grew to love during the Commodore 64 era, and also meant that eleven years later I could revisit the title in an entirely new way. DOOM's the only game that's given me two entirely different experiences from the exact same content.