So, you have bought Classic Doom and now you want to play it, and the original executable limited for you.
No fear, my friend, since id Software released source code of id Tech 1 engine (Doom, Heretic, Hexen and Strife) you can play your favourite games with some bug fixes, and even with advanced features (jump, freelook, 3d floors and even scripting).

Here a list of source ports that you can find over the internet:

- ZDooM (http://zdoom.org) : is one of the most advanced source ports out there. It supports freelook. jump, scripting (taken from Hexen ACS and extended it), and if IIRC some kind of 3d-floors. Current stable version is 2.7.1, but you can play with more recent versions from here: http://devbuilds.drdteam.org/zdoom/.
- GZDooM (http://forum.drdteam.org/viewforum.php?f=23 , Thanks to Gaerzi): is the sister of ZdooM. It supports all kind of 3D-Floors, dynamic lighting, and the features of ZdooM. Watch out: the version 2.x can be run only with an OpenGL 3.x graphics card (like Radeon HD 5770) . Here version 2 (currently in beta) : http://devbuilds.drdteam.org/gzdoom/
- Zandronum ( https://zandronum.com/): another fork of ZdooM. That version is focused on network gameplay
- 3DGE (http://sourceforge.net/projects/edge2/files/3DGE%20binaries/): another advanced source port. It's similar to GZDooM.
- Vavoom ( http://www.vavoom-engine.com/) : Another advanced source port.
- Chocolate Doom(http://www.chocolate-doom.org/wiki/index.php/Chocolate_Doom): you want try the old-school gameplay? With this source port the original bugs are still present, the static limits are still here, and it can play the old demos. This source port have some forks: Chocolate Strife and Chocolate Strife
- Boom (http://www.teamtnt.com/boompubl/boom2.htm) : is the oldest of advanced source ports. It runs under DosBox, but have some neat features like BEX patches (an extension from DeHacked patches). Some static limits have been raised/removed
- PrBoom+ (http://prboom-plus.sourceforge.net/): some improvements over Boom, and it can run under Windows.

This is cool, but doesn't answer all the questions I have. Mainly, how do you use one of these? I tried installing Zdoom, got an icon on my desktop but clicking it does nothing. Some explanation of exactly what Source Ports are, and how to make them work would be greatly appreciated

hi there. Most of the source ports need having original WADs (like doom2.wad or doom.wad, by the way those are called IWAD from Internal WAD) inside their directory. If you want to use ZdooM based ports you could use a GUI: ZdooM Exectuor: http://zdexe.sourceforge.net/

Or you could just copy them to the same folder that the WAD file is in:

Doom 1 - C:\GOG Games\DOOM

Doom II - C:\GOG Games\DOOM 2\doom2

Final Doom - C:\GOG Games\Final DOOM\Plutonia & GOG Games\Final DOOM\TNT

C:\GOG Games being wherever you install GOG games. Then just right click the exe from the sourceport and click send to desktop for a shortcut. Then just double click that shortcut rather than GOG's one.

FYI for DOOM 2's Master Levels I used this (assuming your using ZDoom)

http://maniacsvault.net/projects

And download Unofficial Master Levels for Doom 2 Patch run it and show it to C:\GOG Games\DOOM 2\master\wads

You will then get another prompt to save the master.wad thats upto you. Then run zDoom for Doom II then close. Navigate to the folder and double click zdoom-Username.txt

Then find:

[Doom2.Autoload]

and add:

Path=C:\GOG Games\DOOM 2\doom2\master.wad

Save then when you go to new game in the games menu you will get an option to run the normal maps or ML.

I have tried PrBoom and it does not like Windows 8.1. I'll stick to ZDoom.

-EDIT-
How about Doom Retro? http://www.doomretro.com/

never used. It seems an extended version of Chocolate Doom. I'll try it :-)

To easily use this Wads you can maybe use a Frontend or my. I'm workin at my freetime for a Launcher.

- Support Doom1/ Ultimate, Doom 2, Plutonia, TNT, Heretic, Hexen, Strife, HacX, ChexQuest etc..
- Support 64 Wad Files inc Hash Check
- Support 15+ Source Ports
- Configurable wad, deh, bex, lmp, pk7, pk3, zip lists
- Inbuild Textviewer
- Manageable tool to Configure idtech1 Games
- etc

Look at
My Homepage
or
Doomword Forum Thread

For other Launcher i recommend serach at zdoom Forums, Doomword Forum or Doom Wiki :)

greetings

I've always just used Doomsday (dengine.net). Seems to do the job well and is still being maintained.

This address is outdated. Apparently Herr Oelckers cannot access his osnanet site anymore. For getting new versions of GZDoom I suggest bookmarking instead this forum.

For example, the last version on osnanet is 1.8.02 from June 2013; but if you look at the forum you'll see the current versions are 2.0.05 and 1.8.10 from December 2014.

For ZDoom specifically, I suggest reading ; for source ports in general I suggest looking at [url=http://doomwiki.org/wiki/How_to_download_and_run_Doom]this and that.

Some information on how to choose a source port

Source ports are developed according to different goals, depending on what their authors intend to do. We can broadly divide them into a few opposite categories:
1. Faithfulness. The intent is merely to port Doom to modern systems, not to add any frill or whistle to it. The best example of this is Chocolate Doom, a sort of pun on the saying "vanilla Doom", which goes as far as making sure to glitch and crash the same way the original Doom did. Alternatively, try PrBoom+ which does offer several "compatibility levels" so it can work like vanilla or like a more advanced port, Odamex which strives for a purist option for multiplayer, and Eternity which tries striking a good balance between faithfulness to original behavior and allowing modders to use new features.
2. Extensions. It's Doom but advanced, with bugs fixed and more features, etc. The best example of this would be ZDoom, or its OpenGL variant GZDoom. Alternatively, look at Eternity, 3DGE, or Risen3D.
3. Offline competition. Doom has an active speedrunning scene, and the way speedrun demos are recorded depends only on player input, so everything (monster reactions, etc.) makes use of Doom's predictable RNG. This is very fiddly and can easily break, depending on the version of the game used and even in some cases on accurately emulating glitches. If you want a port that can run demos without desyncs, you have a lot of very precise work to do. The best example here would PrBoom+, or its OpenGL variant GLBoom+. Alternatively, you can look at C-n Doom.
4. Online competition. This basically requires rewriting Doom's netcode to use a client/server architecture, because Doom's multiplayer code was originally written for LANs, not the Internet. The three names you need to be aware here are ZDaemon, Odamex, and Zandronum.
5. Eye candy. Doom used blocky pixels and low-res sprites, with a simplistic lighting model, and sometimes people think it'd be better with polygonal models, high-res textures, and advanced lighting effects such as faked radiosity, glowing lights, etc. The best example here would be Doomsday or its fork Risen3D. Alternatively, GZDoom with a few mods has a good potential, and for a simpler type of eye candy you can try Doom Retro.

You can meet several objectives, but not all at once.

Or, just look at the list of ports here :

http://www.doomworld.com/classicdoom/ports/?platform=2

UPDATE: I just grabbed the Ubuntu 64 version of GZDoom 3. blah-blah... Love it! I'd been using ZDoom on Linux Mint for a good stretch, but this version edges it out by a mile without needing Wine. Gracias for the heads up.