With the BFG edition of Doom 3 out, we thought it might be a good idea to compile a small guide on the Boss fights in the game as well as those of the expansion. Following guide has precise boss battle tactics you can use to defeat the most bad-ass of enemies in Doom 3: BFG.
Vagary is a female spider that can use telekinesis; she’s actually just a regular enemy later in the game – this is just considered a boss fight as it’s the first time you meet one of these.
Just keep dodging her telekinesis attacks and let her have it with whatever you have ammo for. The Chaingun works very well for this boss.
You must fight the Guardian in Hell in order to gain the soul cube weapon. A sort of ‘exploit’ way to kill him is to enter the portal with the BFG equipped and let the cut-scene finish. Firing off a fully charged BFG shot at his blue energy sphere right then should kill him.
If, for whatever reason he doesn’t die, continue the fight while utilizing the pillars and corners as a cover. Shoot down the aerial minions first. Once you kill these, aim for the huge energy sphere above the boss, and he should go down before long.
This boss is actually a mutated Sergeant Kelly. The easiest way to kill him is to make sure your Soul Cube is charged when you enter the room, then right when the boss says the word “welcome,” launch the Soul Cube as well as FIVE rockets, and he should be defeated in short order.
CYberdemon is the final boss of the game. Do not be intimidated as he is much easier to beat than you might think, even on Nightmare difficulty. Simply maintain your distance from him as much possible and keep dodging his missiles.
Use smaller enemies to charge the Soul Cube, and then launch it at him a total of FOUR times. Four fully charged Soul Cubes will kill the Cyberdemon.
The first boss of the expansion, and can only be defeated by grabbing the blue-ish green fireballs that are launched at you with the Grabber and throwing them back at him.
Be careful while aiming your throws, as he can use very high bursts of speed to seemingly teleport. Five direct hits from the fireballs will kill this boss.
This boss is more aggressive than the previous boss and has two attacks. One is a leap like melee attack; the other is once again launching fireballs. When the battle starts, use the Helltime power of the artifact immediately and proceed to fire the Super Shotgun into his heart.
He can only be harmed while he is in his ‘berserk’ mode, which is denoted by a rise of flames around it. In this state, his chest is open and his heart is exposed and glowing.
The third and final hunter, this guy is one of the hardest boss fights in Doom 3. He is powered by three coils in the room that grant him invulnerability and the only way to damage him is to destroy one of the coils, as this will result in him being weakened for a short amount of time.
Activate the Artifact in these critical moments and unload with whatever you have. Eventually, the coils will re-activate, and you will have to destroy another to damage him, until all the coils are gone and his invulnerability goes away.
As the final boss of the RoE expansion, the best way to tackle this boss is to use the Bloodstone and then unload rockets into him while he is flying. Using the Grabber on the Forgotten Ones that fly out to you would be a good idea.
Dodge his attacks and when he lands, pump him full of BFG rounds, and he should go down fairly easily.