DOOM

This is a boss fight

The fight is in 2 phases.

1st Phase you will fight him in a big circle room and will perform a variety of attacks.
If you can keep the BFG ammo for the 2nd phase has they are more usefull there

1. Normal Rockets fire.
He will fire 4-5 rockets (one at a time) from is left hand.Just move left or right to avoid them. They are pretty slow and easy to avoid
2.Mortar Shot.
He will sent a volley of rockets in the air. Look on the ground and stay out of circles
3. Charge Shot.
A big glowing orb will appear on his left hand. At the end he will fire a very quick laser like shoot. You can avoid it by moving out of the way at the last moment or prevent him to shoot it by either doing enough damage to him or shooting the canon. If you prevent him from shooting, he will be knock back a little and will drop ammo and health.
4. Charge.
This is a normal charge. Nothing special about it. Just move out of the way

After beating him, a small cutscene will trigger and he will revive for one more round.
In this phase he has the same attacks has before plus two new ones.
5. Walls
He will create two walls on your left and right forcing the fight in a corridor. This attack does no damage but considerably shrink the room you have to move. He will not do all of his attack during this time but he will do his normal rocket shots and the new attack of this phase (Blast Wave). So far i only saw him do these attacks while the walls are up. Also the BFG is very usefull here since it breaks the walls when it detonate.
6. Blast Wave
He will sent 2 Blast wave your way. One at leg level and the other at head level. You jump over the low one and duck under the high one. It is possible to dodge them by moving left or right but this will require you to be at a good distance from him since the wave are quite big.

In both phase he has the same amount of Health.

I'm only posting here to those who have got themselves in the same situation as me.

I started the Boss fight, unleashed 4 kick ass loads of BFG and killed the MoFo so quick his head was spinning ... but then the re-spawn in hell ... literally!!!

First, at this point, you CAN NOT get out of the level, you are stuck in 2nd stage re-spawn, but not all is lost ... truly, I'm a hack at best and I kill him after about 2-3 hours of trying nearly every gun combo I could ... IMHO if you don't have BFG you'll need to make use of all 3 families of ammo/guns: Shotguns, Bullets & Cells

I also tried re-playing level 8 and having my armor up at 200 and my BFG re-stocked ... no luck!

I was really pissed when I realized I had used up my BFG in the first phase of this fight and even more so when I realized I couldn't get out of the level, I was stuck in 2nd stage boss fight hell.

Eventually I realized my RUNES were no longer helpful ... I had all 3 setup for Glory Kills, and since it's only one BAMF BOSS, that was a waste, so I changed my RUNES for a tiny bit of help: DAZED, EQUIPMENT POWER & SAVING THROW.

Ultimately, and only having used this method twice, my weapons of choice to bring the boss down were 1) Super Shot Gun - this seemed to have interrupted many of offensive strikes and I continuously went for face shots and before I knew it I had him down to half on the health bar.

2) Unleashed every micro rocket and 3) finished with Siege Mode Gauss blast.

I had tried and was pretty successful with Precision Bolt Gauss headshots, I found this brought him down to 1/3 with continuous face shots, but for me, being zoomed in was more of a pain for my own game play, same with other zoom in modes.

Again, I was SUPER frustrated, but kept at it for a few hours and I'm giving my hard fought experience ... not the use these two runes, never get hit, and you'll drop him in seconds, nearly ruin the game for me ... I'm that fucking great .... ya, sure, great solution, blow me.

Anyway, hope this helps someone else!