Doom: Primer Guide

Published: 2021/03/09

Last updated: 2021/03/20


DOOM has a lot of terminology associated with it. Following is a list of external terms and their definitions, sorted relationally:

IWAD differences

The two most-used IWADs are DOOM.WAD and DOOM2.WAD, with DOOM2.WAD being the most popular. There are also TNT.WAD and PLUTONIA.WAD (Final DOOM), but the gameplay elements remain unchanged and they are almost-compatible drop-in replacements for DOOM2.WAD, the primary difference in that case being the textures and intermission texts. Similarly, FREEDOOM1.WAD and FREEDOOM2.WAD are Free Content replacements for the commercial IWADs that are fully legal to freely distribute (though the graphics are near-universally regarded as terrible).

The major differences between the two IWADs are as follows:

Episode structure

Intermission screen

Weapon selection

DOOM features 8 weapons, balanced relative to each other. Weapons come in two types: projectile (launches something which can be potentially dodged) and hitscan (fires immediately with no visible projectile). All weapons work off of a dice pool instead of direct damage values, allowing for some minor variation in damage output. They are as follows:

Doom 2 changes the make-up a bit by introducing one more weapon:


Doom 1 has a fairly extensive bestiary, presented here by category:


Former Humans



Doom 2 expands the bestiary a fair amount, as follows:

Doom II

Former Humans




Items are all the same in both titles with the exception of the addition of the Megasphere in Doom 2, and can be roughly broken down into health, armor, and utility categories, with two cross-overs.


The player starts the game at 100% health. Some healing items can increase this to a maximum of 200%.


The player starts the game at 0% armor, with the category defaulting to green security armor, which absorbs 1/3 of all damage. This category can be altered to blue combat armor if said armor is acquired, which then absorbs 1/2 of all damage. The category will stay on combat armor until another full set of security armor is picked up. Like Health, armor maxes out at 200%. Absorbed damage is deducted from the remaining armor points; as a consequence, combat armor degrades more quickly than security armor.



Terrain features

The Doom terrain itself can be deadly, and it can also be used as part of a puzzle. Some notable features:

Difficulty levels

The biggest decision you make will be the selection of difficulty levels, of which DOOM has 5. Difficulty levels affect, based on the map’s design, the placement (or even occurrence) of monsters and items, as well as a few other details:

|Skill name          |Thing placement             |Ammo/Unit|Special                                |
|I'm too young to die|The same as in HNTR         |Double   |Players take half normal damage        |
|Hey, not too rough  |Least numbers or strength   |Normal   |N/A                                    |
|Hurt me plenty      |Default numbers or strength |Normal   |Used by default                        |
|Ultra-Violence      |Greatest numbers or strength|Normal   |The only acceptable difficulty         |
|Nightmare!          |The same as in UV           |Double   |No cheats, fast and respawning monsters|

Strategies and Hints

Doom is usually a game of fast-paced action. Herein is some advice for navigating it:

Enemy-specific hints

Every enemy has particular patterns, attributes, and behaviors that can be exploited.

Former Humans



Finding Secrets

Doom is known for having a lot of secrets, some being quite elaborate, especially in player-made maps. Generally, there are several things to look out for:

I came here to awoo at you

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