Out of all PC games that have been around for decades, id Software’s DOOM is probably one with the largest longevity. People still make new levels for it, write new engines and modifications for it, and do speedruns for it under a variety of conditions, with new records still being broken every now and then. For almost every piece of hardware which can output graphics and run code, there have been attempts to port or clone DOOM, with “It runs Doom” becoming a popular internet meme.
I’d say there are many reasons for such longevity: the fact that the code of the game has been open-sourced and is since available for anyone to build upon; the well-designed separation of content and engine that makes it possible to add new levels, graphics and sounds just by applying an additional WAD; and last, but certainly not least – the fact that it’s a well-designed game that vastly improved on its predecessors and became a success that was very hard to properly replicate.
getting the game
Nowadays, getting yourself a copy of Doom is pretty easy. You can buy both DOOM and its sequel (and the addons) on GOG or Steam:
“The Ultimate Doom” is the most up-to-date version of the first Doom game, as released in 1993 and updated in 1995 with the addition of the fourth episode, “Thy Flesh Consumed”. It’s divided into 4 episodes of 8 levels (plus a secret level) each.
“Doom II: Hell on Earth” is the 1994 sequel to Doom, which expands on the original with a set of 32 new maps, new enemies, a new weapon (the Super Shotgun) and new power-ups.
“Final Doom” is a collection of two 32-level WADs, created by outside developers for id and released commercially. These include “TNT: Evilution” and “The Plutonia Experiment”. Both are known for their increased difficulty (and especially Plutonia) over the original game.
“Master Levels for Doom II” is an even later set of 20 WADs (each with one level), also created by outside developers for id and released commercially.
All of these will include the games' WAD files, that you can copy and use with any source port. The Steam versions of Doom and Doom II use a pretty okay source port based on the Unity engine with some improvements (like widescreen support and higher-resolution display), whereas all the other games and GOG versions package the original games with DOSBox.
The versions that have the Unity engine also include a separate WAD file that adds new widescreen graphics to all officially-released games. In addition, there are edited graphics and sounds for the secret levels in “Doom II” designed to be more appropriate for the game’s distribution in Germany.
Either way, they all include the WAD files, which can then be easily used in any other source port of your choosing.
If you don’t want to buy the original game, you can instead check out Freedoom: an open-source from-scratch recreation of Doom’s assets with all-new levels, graphics and sounds. “Freedoom: Phase 1” fills the role of (and is compatible with) Ultimate Doom, and “Freedoom: Phase 2” substitutes for “Doom II” and “Final Doom”.
However, the best play to way classic Doom is by using one of the many source ports that exist for the game. These can provide extra features, more customization, online multiplayer and support for different game mods.
Chocolate Doom is the most basic option. It adds as little as possible and is most useful for people who want the most vanilla-like experience on a modern operating system.
Crispy Doom is a variant of Chocolate Doom that aims to be more user-friendly and nicer to the eye while still remaining 100% gameplay compatible. It doubles the game’s screen resolution, adds a widescreen option, changes the default controls to the more commonly used
WASDsetup and adds support for “limit-removing” WADs (ones that, while not using any custom features, may require more than the vanilla Doom engine can handle).
Doom Retro is another port based on Chocolate Doom, but this one adds lots of extra visual features. Instead of having a GUI where these features can be set, it uses a Quake-like pop-out console where commands can be entered and variables can be set. It also introduces a number of bugfixes and improvements to the default game – but at the cost of being unable to make or play “demo” recordings from the original games.
PrBoom+ is a more extensive source port derived from the “Boom” family. It adds widescreen support, an in-game menu where all the extra settings can be edited, an optional fully-3D OpenGL renderer and other interesting features. In addition, since the “Boom” source port added lots of extra features for map creators, PrBoom+ also supports them. However, it also tries to preserve compatibility with the original game whenever possible.
GZDoom is the most powerful of all Doom source ports. Not only does it introduce such features as widescreen, 3D rendering, mouselook, jumping, crouching, a new physics engine, and tons more, it also lets mod makers customize the game itself in a wide variety of ways. All the cool mods that implement tons of new weapons or monsters or turn Doom into a completely different kind of game are typically made with GZDoom in mind.
Odamex is a multiplayer-oriented source port that’s perfect for running traditional-style deathmatch and cooperative matches. It’s based on an earlier version of ZDoom and is more traditional in its design, but still offers many of the extended features from Boom and ZDoom.
Zandronum is the more extensive multiplayer source port. It is derived from a relatively recent (but still a bit old) version of GZDoom and offers many of its features, and is able to play many of the mods designed for GZDoom.
Doom Legacy is a source port with an interesting, well, legacy. While still actively developed, it’s not as popular as it was before. But it has served as the base for a popular total conversion, “Sonic Robo Blast 2”, which turns Doom into a unique Sonic the Hedgehog fan-game.
Limit removing: SIGIL, a fifth episode for Doom 1 designed by John Romero, one of Doom’s original creators
Boom: Ancient Aliens
Boom: Stardate 20X6