How in gods name do you beat deathshead?

Seriously, for Christ's sake, fuck his second stage.

It seems literally designed to drive you to suicide. "Hey, lets make an unkillable bullet sponge that three shots you, place random areas of environmental damage with the logic and precision of a chimpanzee on adderal, and have your only two weapons be the shitty pistol you get at the beginning of the game and a laser that takes 5 minutes to reload, but only out in the open. Oh, and y'know cover, the main mechanic of the game? Yeah, fuck it. We DOOM now boys."

I'm on my fucking 19th try. If I die 3 more times I'm deleting this fucking game.