[Ion Raptor]

You have a good outline for a story, but it's not a story yet, for instance:

"Captain Maximus roared in fury as he charged, his warriors behind him, the royal swords, were not going to die on some backwater world on the eastern fringe, not by the lackeys of the dark gods, not by the Tau, they were not going to die, they were going to live, live and fight for the Emperor, but not here, not on this blasted hellscape, this last, crumbling ruin was the last bastion of darkness on this planet, and the spaceport lay just beyond, the shining light docked, awaiting their arrival, thunderhawks could not fly to pick up Maximus and his forces, for fear of getting downed by the flak cannon that rested in the heart of the blasted complex"

That's one big run-on sentence and needs to be corrected. I think you're trying too hard at this. Remember, this story can be as long as you want it to be. you don't have to crush everything together. get a piece of paper and rewrite an outline for the story like so:

1. Description of scene

2. Maximus introduction
--a. why are they there?
--b. problem?

3. Charge scene: first bunker
--a. grenade
----1. effect?
--b. charge opening
----1. first kills
------a. marine 1
------b. marine 2

4. Ending


That's what you have so far, expand on this and then fill in the blanks one at a time, slowly expanding the story, then re-read and expand again if you want to.


Chears and good luck!