Enders Game Short story

Please help me improve this! I got a 78 on this for ELA, and I would like to see some improvement in my Average(RIP), So can someone tell me what I did wrong? Thanks!

The mortars of the two legged species almost immediately introduces themselves by thundering onto the hulls of our hyperspace command ship as soon as we ingress ourselves into their atmosphere. Looking down, the whole of the ship can instantly make out thousands, if not millions of the strange creatures, ready to give us a welcoming. As our craft makes our way through the troposphere, they visibly tense, their shoulders hunched, unsure what was inside the approaching spacecraft. Our ship touches down onto the soft, brown mud of the swamp we landed in, and the doors open. “It’s time to fight”, I relay to my subordinates, as we charge off of the ship into an oncoming army.
Immediately, there are loud flashes and bangs, from these sleek black objects held in what seems to be some sort of holding limb on the creature’s bodies. As the steel rain from these objects pelt onto our bodies, the humans become visibly worried. Maybe it’s because the rain of fire from the objects simply bounces off of our dark steel armor, or perhaps it is because that we have been preparing for millennia upon millennia for this encounter, I do not know, but I instantly recognize that this will be an easy victory for us, that they stand no match for our superior weaponry. Chuckling at the imminent demise of these puny creatures, I relay to my subjects to open fire. Almost instantly, waves of pure green energy is generated from the sleek power crystals in our armor, and in the next instant, it is all released. More than 99% of the original army is completely vaporized, and then sent to another dimension. Dazed, the survivors of the blast huddle together in a group, unmoving, like deer caught in a truck’s headlights. I relay to my subjects to move on, this would be the easiest battle yet. We begin our approach through the fecund, brownish murk of the swamp. We crawl through mud, algae, and other infested objects, and they still seem to be stunned. “What fools, these creatures are. They do not deserve a planet this magnificent, with flowing water, beautiful green forests, and mountains that rise beyond what the eyes can see. We will take it from them, and give it to the worthy of our species”, I excitedly tell my subjects. We are 100 feet away, and there is still no movement from the species. We are 25 feet away, and there is still no movement from them. We are 10 feet away, and there is still no movement. Finally, when we have the measly group of 100 creatures surrounded, they turn onto us. They fire all the weapons that they have. 30 seconds later, all of them are out of ammunition, and we just stand there laughing. “This species is so foolish, so there isn’t a single possibility that our incredible army can be defeated by this small force of low level creatures”, I think to myself, unsheathing my blade while approaching this weak group of individuals. As soon as I start approaching, however, the fear instantly starts radiating from the group of humans, the will to fight evaporating from their bodies. They slowly, step by step, inch by inch, start backing away from my army. “What fools, you cannot outrun us, hide from us, or even stop us. We will find you, and your painful death will be slow”, I tell to them in their strange dialects, with glee in my voice. My army of millions breaks into a run after them, and we begin the chase. We march through the swamp, and then across endless paddies of rice, crossing small towns, and even rivers. We chase them until the light fades, and it rises again, until we finally chase them into a valley, surrounded by high snowy peaks. “Its game over”, I say to them, in their strange language. “Yes, it is game over”, he replies, determination in his eyes, while pointing up. Instantly, thousands upon thousands of what can only be high energy bomber planes appear out of nowhere. In the instant after appearing, they all start the same process. Millions of large objects fall from the sky, radiating pure green energy. I am somewhat confident in the making of our armor, but there is a chance this will be our demise. I led the army into our own fate, thinking that this couldn’t happen. I baited them into this trap. In the instant before detonation, I think to myself, as hatred bubbles up. “This won’t be the last you see of us”.