DOOM Eternal is far from being easy. Its arcade gameplay is very enjoyable, but it's also very easy to get slaughtered in a few seconds. Here's a guide to get started.
Keep moving
Demons are plentiful, fast and aggressive. If you don't move and don't take side steps frequently, you're dead. Use and abuse double jumps, climbing, and dash afterwards. Keep shooting. Don't forget to search the rooms and pick up the loot.
Get as many Glory Kills as you can
When a demon is weakened, it will stop and then shine in blue (then orange). By approaching and using a melee attack, it will trigger a bloody execution scene, a Glory Kill, which will give you some precious life.
Use the chainsaw often
You have very little ammunition and there are many enemies. The chainsaw recharges a bar of fuel over time, so use it whenever you can to kill a small enemy (imps for example), which will give you plenty of ammo. If you ignite it first, you'll get bonus armor.
Don't forget your powers
It's going to take practice to manage everything, but by making good use of the Flamethrower, Frag Grenades, then Ice Bombs and the subsequent Blood Punch. You'll have plenty of cooldown techniques. The Ice Bomb is your best friend as it will be able to immobilize a large group of demons.
The right weapon and the right mod for the right situation
All weapons are useful, and with the lack of ammunition, you'll have to swap them often. There are many combos to make and weak points to exploit. For example, the Sticky bomb from the Shotgun on the Arachnotron will destroy it instantly. This same bomb, fired into the mouths of the Cacodemon, will make them vulnerable to a Glory Kill. The plasma rifle will explode the blue shields. Consult the codex to learn the weapon tricks and the demons' weaknesses.
Use the map
The levels are sometimes quite twisted and involve long jumps into the void. The map will help you see which way to go. It's especially useful for finding climbing walls.
Look for secrets
Collecting Crystals, Suit Upgrades, Slayer's Gate Key, Weapon Mods and Extra Lives will strengthen you. Killing enemies and performing optional battles will earn you Weapon Upgrade points. Don't forget to allocate them regularly.
Open the gates of the Fortress of Doom
Between missions, you can use your Sentinel Batteries to unlock loot in the Fortress of Doom. You'll need two for each gate. We advise you to start with the 2 Sentinel Crystals at the bottom.
In case of a problem, let the BFG do the talking.
Special weapons obtained during the course of the adventure can change the game. The BFG 9000 can instantly destroy a huge group of demons. It can also help you finish off a Slayer Gate or a tough optional battle. The Crucible can wipe out almost any demon in one blow.
Against the Marauders
There's no miracle technique when you get to this point in the game. Clear the area of the most dangerous demons, and stand halfway to the Marauder to get him to unleash his melee attack. When his eyes glow green, the Marauder is exposed for a short period of time. The best weapon in this case is the Ballista or Supershotgun, followed by a shot of Flamethrower or even grenades. Think of killing his orange dogs too, and move sideways to avoid his energy attacks.
