Hokay. Let's start with thoughts while reading.
Gaols - you make that sound like an invented creature. You do know it has a
different meaning, right?
As she watched, one of them climbed the ladder with a machete and began hacking down the melon sized spapa fruits.
Climbed the ladder
carrying a machete would be more clear. I got this image of him using the machete to climb the ladder. It ended comedically.
When Phay is sitting in a bush at the side of the road having her moment of indecision, you have her start infodumping. Reign that in if you can.
Her decision is made strangely—she decides to go to the city, but her feet have a different idea and then her brain instantly changes its mind. I think I know what you were aiming for, but you missed.
Sorry Colonel. I know I’m a dirty thieving murderer, but I happened to see this glider . . . It sounded lame, even inside her head.
It didn't sound lame to me. That's exactly what I was expecting her to do.
In the darkness, the glowing runes on the first man’s armor shown like a blazing sun.
Shone. I've noticed this is a frequent mistake for you. Shown for past tense of show. Shone for things that done shined.
End thoughts while reading.
Now, I'm going to have a hard time being harsh as requested, because this story is about 3/4ths awesome. The beginning was great; it sucked me in immediately, and the rest of the piece mostly kept me engaged.
I could have wished to know a little more about the boy she met on the roof. He's a throwaway; Phay doesn't even think about him, but I wondered the whole piece what her relationship was to him and if she felt any loyalty towards him. But actually, he doesn't seem to serve any purpose in the story.
Right off the bat, I could tell you were in trouble. The story had the feel and trappings of a novel. It seems you noticed this about halfway through, and started rushing. Well, you're not going to like what I have to say next: I think this could make a great novel. It doesn't work so well as a short. This is where the quarter that isn't awesome comes in. To turn it into a short would require major plot surgery. I don't even know where to begin advising you on how to do that.
Beyond that, everything was a bit predictable. It was quite obvious that she was going to wind up making friends with Bubba, from their very first contact. I don't know if this was your goal or not. Also, it was quite obvious from the way the Colonel treated her that he was trustworthy, and the Sun Guard was safe. I think you could up the tension if you could manage to convince us that these are a shady bunch, and Phay might actually be in danger. It's in-character for her to be slow to trust, but it falls flat because the situation looks so unambiguously safe to us readers.
In fact, because they were so obviously trustworthy, I kept waiting for their secret sinister dealings to be brought to light. That never happened. Don't get me wrong, I like that they're trustworthy and good; I'm just pointing out what all the other stuff I've read has taught me to expect.
About the Sun Guard: what are they for? It appears as though they're a paramilitary organization, and the government should probably be mistrustful of them. But, then, it also looks like they're a boy scout club. They're too nice and cuddly for me to take them seriously as a training ground for actual soldiers. We know that the Colonel is trying to do something good with his life that doesn't involve killing people, but we don't know what good the Sun Guard is supposed to be doing, or what its goals are.
Also, how is being in the Sun Guard supposed to get you set up with rich suitors? That's never made clear. I don't see how that could be true. Another casualty of the story's chopped length.
I thought Phay's wounds healed too fast. Two days is not really enough time for a serious infection to clear up, let alone for the wound to heal, especially in the absence of antibiotics. Yet, after she wakes up, we never hear another word about the gouges on her back or the bite on her arm, both of which should still be healing and slowing her down.
It was also quite obvious from almost the start that Phaylyn was going to wind up being special, which would earn her a privileged place in the Guard and get her all buddy-buddy with its leadership. I kept waiting for it to happen so we could move past it and get to the interesting bits, namely her training and further exploits. Phaylyn is rather similar to Vin in many respects; you'll note that Vin's acceptance into Kelsier's crew was immediate. It was the
beginning of the story. It makes for a pretty crappy ending.
But, well, I love the way you write. Your characters and scenes are always so clear. Your magic systems were alright in this one; nothing special, but good enough to serve.
I also liked the hints of steampunk. Yet another tidbit left undeveloped because the story was too short. And when I say a 12,000-word story is too short, you know you'll have some work to do if you want it to be an actual short story.
So, I hope you do something with this idea. You could maybe get a short out of it, but it probably wouldn't much resemble this piece. You could also get a pretty darn good novel out of it, but again, you'd wind up throwing away most of what you've written here. Such is life, right? Whatever you decide to do, I wish you luck.