DOOM 3: BFG Edition

Want to beat this boss in under 10 seconds?

At the end of Central Processing: Primary Server Bank (once you leave the rotating bridge), you will reach Sabaoth AKA Sergeant Kelly. He's on tank treads much like Mutoid Man from Smash TV.

Sabaoth fires a BFG 9000, but the green projectiles can be destroyed with bullets from something like a chaingun. However, the classic-styled strategy of destroying these projectiles and running circles around the room whilst dodging behind columns in not necessary.

The easy method to defeat Sabaoth is simply the Soul Cube. Have the Soul Cube charged from 5 demon-deaths and then hold onto it for this boss fight. Once the boss fight starts, fire an entire clip of chaingun ammo into Sabaoth for insurance that he will die. Be sure to direct some of that gunfire into any BFG blasts he may launch at you. Then launch the Soul Cube directly into him. He will instantly die causing a cutscene and the achievement to pop for 15G.

I believe Sabaoth takes 2 Soul Cube hits to die, so the chaingun beforehand makes sure he's weakened enough to die from the Soul Cube. There's no other enemies to kill during the boss fight to recharge the Soul Cube, so make sure it's charged before you start.

Another easy method for defeating the Sabaoth boss if you don't have a charged Soul Cube ready, is to keep firing while you're really close to him, strange as this may seem. I died like 15 times trying to shoot Sarge from a distance, blasting the BFG balls and then falling off the platform.

The thing is, the BFG is his *only* weapon. There's nothing else he can fire at you. And if you get close to him, he will take a swing at you. And when he's swinging... he's not firing his BFG. Once I figured this out, I took him down in two tries, within 5 minutes.

Just equip the plasma gun or the chaingun, start firing, then walk up to him to trigger his punch, back up a bit so he misses, and repeat. When he goes behind one of the four pillars, keep the pillar between you and him, and once he appears again, start firing and getting close to him.

This is mostly a guide for your NIGHTMARE run but can apply on easier difficulties as well.

Sergeant Kelly now turned into Sabaoth, can be found on Central Processing: Primary Server Bank. Save after exiting the rotating bridge, just before the door at the end of the hall. Prepare a quick switch to your Rocket launcher and equip the soul cube. (You absolutely want a charged cube for this as the tendrils from his BFG shots can kill you on nightmare long before you are able to shoot them to disrupt them.) Run into the room moving to the left pillar, and immediately, as the door containing Sabaoth starts opening, throw the cube and switch to your rockets. Pop behind cover every shot to prevent him from firing the BFG, and he will go down in 5 relatively quick rocket blasts. Below is a video.

*the pillars can electrocute you if you're not quick enough but I've done this on 3 different versions of the game on all my nightmare runs and it works quite well.*