How do you defeat deathhead?

On the roof. Use Laser Kraft Werk (LKW) to cut a hole in the fence behind the shield. Grab armor and life points quickly (weapons later). Run/sprint along the fence picking up life points as you run left or right turn and run back to the building, up the stairs back the cannon mounted on the corner. Get in the seat, elevate and shoot down the first blimp. Exit the cannon, jump over the railing and run to the other cannon to shoot down the second blimp. Jump back over the railing back through the hole in the fence and throw Tesla grenades at Deathshead.
After the explosion blows a hole in the roof, collect every weapon, rocket and Tesla grenade you can carry. Do not collect life points until you are loaded up! Once ready, load rockets on both assaulr rifles, set to fire. Grab life points and drop through the hole in the roof. Locate Deathshead, throw Tesla grenade, fire one rocket and MOVE! Repeat picking up life points and goodies. Oh, avoid the gas jets. You take it from there.