He opened his eyes. One, two, only two eyes on the right; the others were crisped.

He remembered examining a console, but alarm was rigged and everything went white. It's likely a powerful explosion that crippled him, self-destruct sequence perhaps; the Endless were always cautious.

Tried to turn his head, the sound of his charred skin crackled echoing the ruin. Maybe Ammoh were right, he was too big and old, 427 years too old, to be an archeologist. But this is not the time to think of that.

His eyes scanned the ruined dome. The team that's with him is dead. Their hamslya's nowhere to be found. Without wind for spore and hard dirt that rendered root connection impossible, there's no way to send for help.

'I'll not die here,' he thought.

If he wanted to survive he need to get out, fast. They're here to check the ruin one last time before 'they' arrived and when they're here, the fahah would be detonated and cleanse the colony. If they're lucky, the invader would inhale the smoke and changed their way for good.

With such poor soil, it's impossible for him to regenerate his whole body. He couldn't feel his left side at all.

There must be another way. Maybe he could accumulate some ruins to replace his limbs.

He looked around, but with the pain from burned bark, it's a difficult and torturous process.

His eyes spotted a data-pillar that normally housed Virtuals Endless, but after many clean up he doubted there's any here. They wouldn't miss it.

He moved to the pillar with his remaining strength. Once there, he forced himself into sitting position with his damaged side facing the pillar.

The plantoid rooted his right leg and arm. The roots absorbed barely-existed nutrition from the dry ground.

'I pray for just a drop, Ny-Kibal.'

His left most eye soon recovered. He saw that his left arm and leg were gone. If he had lung, he would sign. With his charred form, he would be marked as a pacang, even though he was not a fighter. Then again, so did his seed-father and he became an assistant to tanggi. 

The progress of regrowth was tedious, but he managed to accumulate the pillar as part of him. With his recovered power, he lifted himself up, along with the pillar.

As he stood up, he heard a calling from another plant. He felt something crawling up his body. It came resting on his arm.

It's their hamsleya. The little pot plant tilted its head.

With haste, connected to it and prepared to send a distress call.

"You had made a terrible mistake, plantoids," A feminine voice boomed.

He gazed to the left where the voice came and discovered that he failed to notice the data-pillar became active.

'Sitting' on top of it, was a virtual golden being.

"Endless," he muttered in awe.

"A ruined cage to a walking one. This is so tiresome, I hope you're a good conversationalist, plantoids."

Author note: If this excess 500 words please tell me. 

Constructive criticism's welcome.

Some wording explanation, because I expect them to have their own language (if you want this section taken out or shorten, tell me):

- Ammoh : community/spiritual leader/shaman/elder of the Unfallen, not truly official authority but well respect and seem as advisor and community guide. Most of the time a individual of 500 years old or more that refuse to turn to serve as guardian. 

Based on South East Asia culture, they are a mixture of Muslim's Imam (SEA Imam isn't like their middle-eastern counterpart, less zeal and less violent), Celtic's druid and Maleysia's Bomah (shaman). In a sense, a lot of Unfallen culture I made is based on South East Asia culture, specifically Malaysia and Indonesian, due to their culture tie with water and plant. So expect some Islamic influrence and Shamanism. I am not muslim by the way, just live in their neightbor country.

-Hamslya: semi-sentience plantoid creature, size no bigger than a sheep at most. Hamslya are plantoid capable of sending out, reflecting and intensify minor energy wave or chemical, don't expect them to reflect laser. As such, Unfallen employ them as communication 'device'. They simply connect to hamslya, like they did with other plant, including other Unfallen, and let them sent out signal to other Unfallen with hamslya who will detect the signal. They also allow communication with other specie if they tuned their device to match the hamslya signal. They are only use outside of Unfallen community as they were their only mean to communicate from isolate location. Beside that they made for great pet. 

They are based on a plant called 'Nepenthes hemsleyana'  which capable of reflecting bat sound wave to lure them in for nesting, with minor inspiration of 'One Peice' snail device. Agian South East Asia plant.

- Fahah: Incinerating bomb used by the Unfallen to raze their own colony in a quick and efficient way. Can be use as unorthodox, or accidental, method of burning themselve to let the offerder inhale their peaceful smoke/drug. (Get high.) Originate from Malay word for sacrifice.

- Ny-Kibal:  A spirit deity in Unfallen myth. Ny-Kibal was regarded as supreme goddess, rival her husband the supreme god.  She rule all water and thus the life giver and savior in tough time. She was often viewed as protector. Rather than some church religion, the Unfallen pray to small shine with some offering or just pray on spot for good luck. An Ammah always keep an amulet dedicated to her. 

Based on, you guess it, Indonesian spirit deity who rule the Indian Sea. Since they are plant, water is the vital aspect to them, so it's natural for them to deitify water in one way or another. Note: 'spirit deity' isn't like Zeus style of building grand temple. Rather it's a small time worship, oftenly locally, not nessecary imporatant part of life, but still prefer to drove bad thing away.

-Pacang: A term used to call the Unfallen who had an obvious sign of burning, as it's very hard to completely recover from burning scar as a tree. The used of fire is forbidden in their culture and is cosider a taboo to make fire without Ammoh approval. When they took to the star and conflict become unavoiable, many Unfallen were left with charred mark from war, usually very large. This make their own people extremely uneasy around them as the Pacang have associated with taboo object, which is fire and war, their other taboo subject as they're pacifistic.

The name itself come from Indonesian/Malaysian ghost of those who come back to life because they have tie to the world. In a way, it's fitting. The Pacang, with their charred skin, looked dead to Unfallen community and the appearance of the original ghost that are wrapped in white sheet is an irony to their black bark.

- Seed-father: The Unfallen, being plant, have variaty of sub-specie and thus, have several ways of reproducing. Our protagonist happen to belong to subspecie that used seeds as a mean to reproduce. That's why he call his father 'seed-father', if he was born from spore he would say 'spore-father. One plant can have many children and can leave them to grow for themselve as all Unfallen treat each other like family, but the sappling always know who their parents are through linking. Not that they're nessecary care as everyone is their family.

- Tanggi:  Sometime called 'Conduit' or 'Mindtree', they are the closetest thing Unfallen have to real leaders and authority, Tanggi are nearly unmovable Unfallen with various size from a small metropolis size to a mountain size that have root spread throughout their world. Tanggi are capable of interplanetary communication with another Tanggi and once in a while they would meet, through link, on their homeworld to discuss issue from if each members is well to whether or not they should scacrifice a colony. They also work as communication center of a sort to all Unfallen on the planet.

Based on Malay's name for ghost in form of a tree, but that's where the similarity end.

- Plant language: Some would argue that Unfallen can link together, they don't need 'language'. Well yes, but it this I make it so that Unfallen are still seperate individual that can joint conciousness momentarily to receive information. With their shamanism that originate from their strong tie to nature, they would have some chant of a sort for their spirit who they may think didn't heard them in time of disater so they called them in words rather than believing they can connect with the spirit like they do to each other. That's why most of their spoken term, that isn't in galactic standard language, are related to spiritual subject.

As of right now when I read the story the word count for the entire story was 630 words, I basically pasted the whole thing into my word processor to quickly check that for you, so you will need to trim down by 130 words to fit requirements. However I like the basis of your story, your concept for the hero (Unfallen/Virtual); your little Indonesian/Malaysian influences; the use of Hamslya, little drones/pets - its great to see some of the writers have been influenced by me; and would like to see your story further refined. 

You can use a website like Word Counter after editing if you want to know where you are at in terms of word count - just paste in the story to check word count and characters.

From the way you have written your story, in third person, I feel you have used "He" far too much and it degrades from the quality of the structure, with a notable string of 5 sentences beginning with "He":

He thought of another plan. Maybe he could accumulate some ruin to replace his limbs.

He tried to look around the dome, but with the pain of charred bark and burned leaves still lingered, it's a difficult and torturous process.

He spotted a database pillar that normally housed the Virtuals Endless, but after many clean up before, he doubted there's any Endless here. There's no reason to waste it then.

He used his remaining strength to crawl toward the pillar. Once there, he forced himself into sitting position with his damaged side on the pillar.

He began rooting with his right leg and arm. The roots absorbed the barely-existed nutrition from the dry ground. It's likely to take some time.

If you are identifying the Unfallen in terms of male grammar then we have a selection of: He, His, Him, Himself, They, Their, Theirs, Them self, Themselves. But of course in a story sense He, His and They, in the same way that first person uses I, Me and My will come up more often. Even structuring a sentence in a different way just to avoid such repetition and using these identifiers in a sentence will improve the document.

If you so chose to you can make the story first person or keep it third person, its up to you how you want to tell the story.

First

I opened my eyes. One, two... yes only two on my right side; I cannot feel the others.

Vaguely I remember, studying that Endless console but it was... rigged? There was such a bright light, was it an explosion... Is that why I cannot feel my left side? The Endless were always cautious...

Third

He opened his eyes. One, two... only two eyes on the right; the others were charred and burnt.

They recall examining a console, an alarm ringing, a blinding white glow and a mighty explosion. Had this long dormant Endless trap crippled him so? The Endless were always cautious 

By no means am I a master of my language but I did these quickly to demonstrate a use of restructuring and usage of different words. Hopefully I've been helpful and I anticipate future edits of your story.