Basic prerequisites to get started playing Classic DOOM mods

How to install a source port and launcher

How to create a functional load order

Recommended GZDOOM settings and changes on a fresh install.

A few things you will need in order to play any modern DOOM mods are:

A Source Port (Usually GZDoom or LZDoom)

A base IWAD (Doom 1, Doom 2, The Plutonia Experiment, TNT: Evilution et cetera)

(Optional but highly recommended) Some form of launcher or mod loader (ZDL, SSGL, Doomrunner, Doom Mod Launcher et cetera)

The mods you are wanting to run (Brutal Doom, Complex Doom, Project Brutality 3.0 et cetera)

This will go over each step of installing both your source port and mod loader/launcher for Classic DOOM. The example source port and launcher we will be using for there are GZDoom 4.7.1 and ZDL.

Step 1: Installing GZDoom.

First, you’ll have to go to ZDoom’s main website and more specifically their download page, that being https://zdoom.org/downloads. My recommended version is the latest stable version of GZDoom if you have a more modern device, or LZDoom if you are willing to sacrifice mod compatibility for performance.

After downloading your preferred version of GZDoom/your specific source port, you should end up with a .zip which contains all the source port’s necessary files in order to run. You’re going to want to create a folder, preferably in a place you can organize your mods within, and then unzip that .zip file with a program like WinRAR or 7zip into said folder.

After that, you’re done installing your source port and can move onto step 2!

Step 2: Installing your preferred launcher.

To start installing your preferred launcher, which is what we will use in tandem with our source port to run our DOOM mods. Once you find your preferred launcher, I will be using ZDL for this example, follow its installation instructions located on its website if shown. For that version of ZDL, all you need to do is download the .zip file corresponding to your Operating System and extract the .exe to a location you can easily access it. After downloading and installing your preferred launcher and making sure it works, you can move onto the next part of the guide.

This will go over all the steps to making a load order via your DOOM launcher to work as well as it can be universally with any DOOM Mods you may encounter. Our example will be ZDL as referenced earlier in the document.

Note: All launchers are different and all mods are different so if there is a better load order or different steps taken to achieve a working load order from that launcher or that mod, use those instead.

Step 1: Setting up your source port.

To even be able to launch our mods with Classic DOOM, we’ll need to specify our source port(s) with our launcher. In ZDL that is under the “General Settings” tab near the top of the window. After navigating to that menu, there will be two large boxes, and the one labeled “Source Ports” above it is where we’ll set the directory for our source port that we’ve installed.

For ZDL, click the small black “+” button at the bottom of the window then navigate to your source port’s directory then select its “.exe” file. This adds our source port to a list of executables ZDL can run when the “Launch” button is selected.

Once your source port is added, you can move to step 2.

Step 2: Adding your IWADs.

IWADs are how the game knows which base files to load before any mods you create work as a “baseline” for mods to work off of. This includes the base games like The Ultimate DOOM, DOOM 2, The Plutonia Experiment, TNT: Evilution, Freedoom 1 & 2, and more. These are different from community-created map sets known as PWADs as these are always required to start the game correctly.

Once you have your hands on any IWADs compatible with GZDoom you’ll have to add and name each of them into your launcher or in this case ZDL. On the same menu that you added your Source Ports, on the other side of the screen is your “IWADs” list which has another black “+” underneath it and that is how you add each of your IWADs. You’ll have to add each of them manually and name them according to what map(s) or games they correspond with.

Once you’ve added your IWADs to your launcher you can move to step 3.

Step 3: Adding your mods

After you’ve added your source port and IWADs, you can switch to the “Launch config” screen of ZDL which is where you’ll spend most of your time adding/changing up your mods for DOOM. You’ll first have to select whichever IWAD you’re needing for a map set or wanting to play along with which source port you’re wanting to use for those mods. After selecting all of that though, you can add whichever mods or map sets you to please via the “External Files” list. The most common forms of mods are.WAD for map sets, .pk3 for gameplay mods/addons or universal addons, and .zip acting as an alternative but very similar .pk3 file. Zip and PK3 files will run just fine with GZDoom and LZDoom although they are not guaranteed with other source ports.

A general load order that works perfectly for most DOOM mods out there is:

Maps → Music Mods → Main/Gameplay Mods → Addons → Custom HUDs.

This will reduce as many load order conflicts as possible and usually should be followed unless specified else wise by a mod or map which is rare. Below are some examples of maps and mods that you may encounter in various types and why they need to be there.

Maps

Maps come first in order for Project Brutality or any mods to override the necessary files to make it compatible.

examples: Hell On the Earth Remastered (DOOM 2 Remastered), Sapphire, Prison Labs v666, Project Brutality Playground

1. Music Mods

Music mods come after maps so they can override any music that the map may have.

Example: Doom Metal Soundtrack

2. Main Mods

Project Brutality and other mods sit here so they can override the map files but don’t override addon files. These mods don't tend to mix well.

Other Examples: Brutal Doom, Hideous Destructor, Beautiful Doom

3. Mod Addons

Supported addons/mods come after your main mod so they don’t get overwritten and cause errors.

Examples: Glory Kills, commander shotgun

4. HUDs

Heads Up Display addons (HUDs) come last in order to get all the necessary items and mechanics integrated into the HUD.

Examples: HHXRTCHUD, CATS VISOR, nekos hud, UDV

After you’ve set everything up in the correct load order, you’re done setting up your classic doom so go have some fun with the game or read through the last bit of the guide to “maximize” potential enjoyment.

Various things I recommend you change in GZDoom’s settings or files to get the best experience out of it.

Note: This is all highly subjective and optional and requires you to use GZDoom.

Simple options menu and full options menu

To get the most performance-wise and gameplay-wise out of GZDoom, you’re going to have to disable the simple options menu. You can do this by clicking “Full options menu” and then disabling “Simple options menu”.

Texture Filtering

A “highly controversial” default GZDoom setting is a texture filtering due to it usually not looking the greatest outside of mods that replace everything with 3d models. It is located in Options -> Display Options -> Texture Options and I highly suggest turning it off.

Clean Menu Scaling

By default, GZDoom has “Menu Clean Scaling” enabled which can cause some weird things to happen with mods not expressly supporting it so I suggest disabling it. In Options -> Miscellaneous options turn “Disable Menu Clean Scaling” off to get rid of it.

Base Keybindings

GZDoom’s default controls can be unfathomable to some who change up their keybindings in various games so I highly suggest going through all of them to make sure they work well for you.

_{Adapted from: Basic Installation Requirements for Doom Mods by Ted the Dragon}