I just really think a sequel from a perspective of a few months later could work. I'd like to see it from the perspective of military, and have it go on a rampage in a few more states, failed military plans, havoc across the country and the whole world... I think it could work.
Actually, with my idea the monster would have to go back to sea, or lay dormant some place... have it be a week, maybe a week and a half... yeah.