|Best done in multiplayer since you can't die. (Indeed, even if you haven't gotten this far in single player and your friend has, you can have your friend host and go directly to this level.) The best way to avoid taking damage is to stick to the sides and avoid staying in the middle whenever possible. Keep an eye out for shield recharge drops which sometimes drop from random enemies.|
The boss will have one stack of smoke billowing out of him when he's at 75% health, two stacks of smoke when he's at 50%, and three at 25%.