Although there are no shortage of modding opportunities available in the market for games such as Doom, there are still some people who prefer to stick to the original game itself. For these people, there are several options available to mod your Doom 3 game. These include the popular mods such as Angelina and Team Fortress Classic, as well as the popular mods like Civil War, Destination Renko, and Defense Base: Archangel. Some of the most popular of these are the "Better Doom" and the "Dawn of Hell" mods.
The "Better Doom" mod is an improvement upon the original doom series, adding new features such as better game balance, balancing, weapon balance fixes, and many more. The "Dawn of Hell" mod packs quite the punch with two new classes: the Terrorist and the Marine, each with their own unique set of skills and weapons. Other additions include the "Haunt" mod, which put the player in control of the environment; the "campaign" mod, which add new missions specific to the doom series; and the "otech pack", which grant the use of plasma rifles and sentry guns. All of these add-ons improve the quality of the game experience, while still maintaining the overall feel and atmosphere that made the original games so successful in the first place. In essence, the "Better Doom" is a refinement of the original; and for those that loved the original, it's a purer, improved version of that experience.