IT IS DONE. MWAHAHAHAAAA!!!

Few issues. Firstly:

Sargent Major Tucker Loomis of the United States Marine Corp, Sniper Division.

...

United States Marine Corp, Sniper Division

...

Sniper Division

...
Come on. If you're going to use an actual force, like the USMC, do some basic research. There isn't a "Sniper Division" in the USMC. The closest thing is that there was a Sniper Company in the 6th Marine Division but that (and the rest of the 6th) was deactivated after WWII. Now there are Scout Sniper Platoons, but a Sergeant Major would not be serving in them. The Sergeant Major rank is a command-oriented rank, serving as the senior enlisted Marine in a unit, charged to assist the commanding officer in matters of discipline, administration and the morale and welfare of the unit. You want to make it better? My recommendation, change the rank to Sargent, Corporal, or Lance Corporal (with an emphasis on the Lance Corporal) if you want to have him be in that kind of unit. Otherwise, change his unit to something like the I Marine Expeditionary Force, 17th Marine Expeditionary Unit (There isn't a 17th MEU in the I MEF [read/pronounce as "one MEF"], but with fiction, something like this would be acceptable).

Second: (Numerous grammar issues.)

...you guys ponies?

There should be a comma between "guys" and "ponies", or put a question mark after "guys" and capitalize "ponies".

Why, yes we are , Darling,

There's an extra space between "are" and the comma, "darling" should not be capitalized.

...the loss of your friends.” Said Celestia.

Period should be a comma, "said" shouldn't be capitalized.

...an awful lot like Call of Duty: Black Ops.

Most people just call it "Black Ops". Calling it "Call of Duty: Black Ops" is awkward.

I fell I can trust you.

"Fell" should be "feel".

HEY YOU THERE!!!

Never use all caps like this. Never. There are better ways to show that someone is shouting. Also, only one exclamation mark. Using it on one word is fine, but multiple words like this is just wrong.

What the-SHIT!!!

Use only one exclamation mark.

...Carousel Boutique here in ponyville...

"Ponyville" should be capitalized.

Come on try again please.” Saying that I gave her the most honest, sincere smile I ever gave anyone before.

Awkward sentence is awkward.

“My-my name is Fluttershy.”I could sense a little bit more courage from her, not a lot but a little.

Missing a space between "'...Fluttershy.'" and "I could..." Also, do not repeat things like the underline bit. You already explained that to us, so we don't need it again.

“There you go.” I said holding

Period should be a comma.

mouths agape mouthing “Howhowhowhowhow…” over and over again.

Get rid of the underlined. Just end the sentence with "agape". The rest of it doesn't add anything to the scene, and only is contradicting the mouths being agape. "Agape" (in this context) means that the mouths are hanging open, while "mouthing 'how'" would require the mouths to be moving, and therefore not hanging.

That's all I got from just my first run through the story, much less everything that is there. I recommend an average of four runs through an editor for a chapter to clean it of most, if not all, grammar and spelling issues before posting.

Number III:
There are a lot of punctuation errors in the dialogue that I didn't point out in the section above. Punctuation, in speech, helps provide tone and context. You need to use it. For example:

"Common Rarity wait for later to ask questions."

This is written so that the whole line is said in one breath, with no pauses. No one speaks like that. However, people do speak like this:

"Common Rarity, wait for later to ask questions."

or:

"Common Rarity. Wait for later to ask questions."

These show a pause between "Rarity" and "wait". The length of the pause depends on whether the punctuation is a comma or a period. Depending on context, one or the other would be preferred, or they could just be interchangeable. A third option would be an ellipses "..." which would be a longer pause than a period, but that wouldn't work in this exact statement (it would be more like "Common Rarity...", indicating annoyance or frustration from the speaker). Reading dialogue aloud would help with determining which it should be.

Point D:
You might want to reread through the Zombies' storyline. The zombies weren't quite created by an "evil scientist" (which, while somewhat true [more "mad" than "evil" though], is way too much of an oversimplification), but rather through exposure of dead people to Element 115. Also, Element 115 wasn't the cause of death of the zombies. What was described by Celestia sounds closer to Resident Evil (which I'm nowhere near an "expert" in the fluff of, so I could be mistaken), than Nazi Zombies, considering that it sounds like the whole thing is based on a virus rather than just reanimating dead tissue through an exposure to an element.

Overall, needs a good editing, but there is something there once a reader gets through the errors.

The guy who unleashed the zombies is called richtofen do some call of duty zombie lore just saying.

5473319 sorry about the first issue it was a stupid mistake. I should have known better. the last issue. i know all of that but i will make a few changes. and as for the rest i will fix my mistakes. thanks.

Was told a month ago the next chapter was almost done *waits a month* finally its here *reads in 1 minute* well that was fast. But oh well i like this story. Now we commence the waiting again.........

5474686 Not for Every long one will not. I got it started but need some suggestions about what should happen in the next chapter.

5473319 you just earned a follow.

You should have Princess Luna come in somewhere.

5552782 She will in the next chapter.

5553131 awesome

Sorry guys but I have to pause here for a while due to a lake of inspiration. any help or suggestions are welcome. Thanks

IS THIS STORY DEAD?

Since this is under the CoD category, make it as if the Shadowman sent the plague doctor (name here) to Equestria to “create an invitation to a world beyond imagination.” Basically Shadows of Evil-esque. Maybe get Primis involved, I’m not sure. Hope these helped.