Project Warlock

This may not unlock, I didn't unlock a boss achievement until killing the tank which is fourth boss. It has been reported and I have had confirmation from the devs Crunching Koalas are looking in. Replaying the encounter and beating the boss again may work but havant tested that yet.

This boss has two stages

First stage you have to run around the arena destroying his tentacles once thus is done your onto stage two and can blast away at his body as he now takes damage.

No real tactic to this one keep strafing and hit him with your strongest gun.