What everyone is saying about it being too on the nose with the theme is correct, and lacking a more focused perspective - as Caracal mentioned - is the biggest thing that could improve this story. For instance, instead of saying that the nameless battle brothers outsmarted and out maneuvered the nameless orcs, try to hone in on exactly what they did that won them the battle. Let the reader see the theme between the lines. Writing a coherent story in under 1000 words is hard, so it's okay to focus in on a small aspect of a potentially larger battle. Perhaps, what did one marine do that turned the tide of a losing battle?
I hope you use all the good advice in these comments and keep writing, there's definite potential here!