I will try to be spoiler free "ish"
This boss has 2 phases, the initial one and the next that changes when the health bar crosses 50%.
During the first part it will pursuit you with his weapon, slowly (since it is very big), and in the meantime if he breaks any of the little towers it will release a regular enemy. Those will be useful to win a second chance if needed.
There is a cycle which is more or less like this on the 1st phase:
- boss pursuing you
- boss jumping up to your location
and so on.
If you jump to one of the balconies above, it will throw you a weapon that will make a bubble around it and hurt you heavily. When you see the bubble if you are there, drop to the floor.
From time to time it will invoke a thunder and a new weapon will appear on his right hand. Now is when you have to leave the floor, unless you wanna die (since it will electrify all of it). Jump to the balcony, and then it will try to throw to you the regular weapon when you are at it. If you are alone it will be just you, if you are playing with someone else and is already above it will have another throw of the weapon.
All of this until the 2nd phase
*** Spoiler - click to reveal ***
The boss will be a giant torso throwing riding bomber psychos at you. The phases will be:
- invoking enemies with rockets at you (those are useful to kill because they drop ammo)
- invoking an energy rainbow that will crush you (try to stay behind a piece of rock floor to avoid it)
- more flying enemies
- Our guide will throw a lasso to the boss, so now it is your chance to really hurt him. Do it on the head with a weapon that has a big magazine and high firing rate. Having to reload will not be good since you have around 10 seconds to do it so.
The cycle repeats until it is dead and his health bar depletes