"Updated version of this game that marked a before and after in action games"
If you are or have been a fan of the whole Quake and Doom revolution, spending hours and hours killing monsters and aliens in some claustrophobic places, then what you need on your computer is a program called Doom Legacy. As its name suggests, Doom Legacy is a free updated version of this successful game that marked a before and after in action games. Adapted to more modern times (much more than the original), it has taken the original source code for the game and made it better.
Doom Legacy isn't just another Doom copy. It comes with a variety of bug fixes, graphics updated to more modern computers with their faster chips, and the graphics engine has been modified to include mods and map creation.
The whole Doom Legacy project philosophy is built around four simple premises. Firstly they've taken the best bits of Doom, but they've kept it simple so you aren't overloaded with complex options. Secondly, in case you were worried, they haven't changed the gameplay. Thirdly they have made it as user friendly as possible in order to share their joy of playing Doom. And finally there are no cheats in the multiplayer mode!