Well hes not really hard. Better than explain ever little detail ill post a video i made of me fighting him. Basically use powerful weapons during this fight and try your best to focus on just one of his tentaicles........yea anyway when it darkens it will fall. Run up to it and you should get a on screen prompt of circle. hit it and run back as a giant laser will strike him down. after this he will drop reward boxes. simply collect and watch the station crash into him.