A military and mystery work? We'll see how this goes.
I now can see that you actually tried to format your story now that I have it in a quote box, with the indentions and all, but the forum takes that all away. Instead, adopt the forum formatting and double space between paragraphs. It's easier to read that way and it's just basic formatting since indentions don't really show up.
So before the above quote, you had a rather long part about how the marines were firing on the monster. Not much description other than, "the marines shot at it. The tentacles waved like they were in a rave and smashed the mast. The marines shot more. The helicopters fired misseles, somehow missing the marines on board and keeping the wooden boat intact. Modern technology was at its greatest now. Marina screamed in her com as the tentacle smashed against her window. The marines shot some more."
Okay you didn't really say that, I added in some of my flavor, which was more for my entertainment than yours. I can have fun too right? But it's really boring to read that. Add in description. I can't stress it enough. You have solid action, but there's almost no images. All I can do is assume what everything looks like. Use your five senses and put that onto the computer screen.
That's all I can say, or feel like saying, for now. So be sure to keep in a few facts in mind and remember to proof-read. You have a few grammar mistakes and typos, which are actually one-time occurrences since I saw that you had the correct usages somewhere else in the chapter.
Good luck and keep writing!