Ahhh DOOM... Talk to any gamer who grew up in the 90's and they will surely recount fond memories of all the good times they had playing id Software's original magnum opus. Wolfenstein 3D may have pioneered the First-Person Shooter genre, however it was DOOM that really brought it into the spotlight. Originally released in December of '93, DOOM would later be re-released with an extra episode, re-labled as The Ultimate DOOM.
At first glance The Ultimate DOOM may seem a simple affair by today's standards, what with it's deceptively simple gameplay. However looks can be deceiving, as the DOOM series is know for it's twisted mazelike corridors. Gamers who are used to the linear games of today could find themselves lost for hours in a level, searching for the next keycard. In the era that DOOM was released the length of a game was provided by actual gameplay, and not by artificially padding the experience with cutscenes every 3 seconds.
The gameplay in DOOM is a satisfying affair in which players must dispatch hoards of hell's minions while searching out colored keycards to unlock the various doors that block their path, all the while searching out the games myriad secrets, which usually results in a serious upgrade of firepower. And you'll need that firepower, as the baddies keep getting bigger and more badass as you go. The best gun in the game, which can be seen below as the player faces off against the Spider Mastermind, is the BFG 9000, AKA the Big Freakin' Gun. It launches a big green ball of energy that will frag the living hell out of anything in it's path.
Another thing DOOM popularized was the fine art of Deathmatch. Players could use their brand new dialup modems to engage each other in bloody warfare, where victory was determined by how many times you could reduce your foes to a pile of chunky kibble. Since DOOM's inception of Deathmatch it has become a staple of nearly every game in the FPS genre since. The Ultimate DOOM is truely a genre-defining game, and if you have never tried it you owe it to yourself as an FPS fan to give it a try.