Purchase all upgrades that allow you to do +3 Devastator attacks, upon max health. Get all the upgrades you can via "Consume". Notice that under her life bar are other bars. These are some what the Boss' stabilizers, making her vulnerable only after you have severed them. At the beginning of the battle she will do a scream attack. Be careful. Scale up a building or whatever else you have to do. It is very easy to avoid. You will also have Hunters and Infected chasing you. Use the full body armor and claws/blade. Max out your health by running around and consuming. It is easy and the only issues you might have are Hunters, though with the upgrades one hunter can nearly boost your life to max, allowing for maximum Devastator attacks. This is one of thefirst Devastator attacks you will learn. Scale a building, boost over to her, fall, and initiate the attack. You will see quickly that the Boss' stabilizers are being damaged. Note: Every round the stabilizers' life will increase, meaning that you have to follow the tactics in the same way (and it will just take slightly longer). Strike her with the Devastator. You should have a chance for more, unless she does multiple attacks (green orbs that track you, spitting concrete and screaming). The armor reduces the amount of damage inflicted, allowing you enough time in between attacks to initiate the Devastator again. Once the stabilizers are done, she will fall and you can attack normally. She will then retreat (leaving you plenty of red life orbs to consume) before shooting out of the ground again, with more stabilizer life and "backup". Ignore the backup. This tactic works great, but if you get low on health, run away from her view and keep consuming. After she falls a total of three times you will have defeated her.