Him? Easy. I can tell you.
First just use mini Chaos Spears(not full charged) to take out the buildings and stuff he chucks at you. then he will send most of it down exept these asteroids which fire easy-to-dodge lasers.(I didn't get hit by them ONCE.) then get up to him and charge up chaos spear until he says,"Chaos...." and then get close to Devil Doom(not so close you're touching his body, a few feet away) and release the button. Doom's Eye will fly out to the other side of his head, so fly around there. He'll probably do a Chaos Control to the other side, so have a Chaos Spear charged up so hit his other side.
Then when he Chaos Controls to the other side go back and do everything I told you to.
Hope that helps.
PS. You'll eventually get a Chaos Control and Chaos Blast here.
For Chaos Control you just have to keep nailing him in the eye and you'll get to use it. It's not as helpful as Chaos Blast cuz it takes forever for dooms eye to get over in chaos control.
Just destroy buildings and stuff for Chaos Blast.