Yo.
Well, that's a depressing way to start off the story- character death. I do hope we find out more about this character later, and more about the wars, the pills, and the falling of governmental forces that led to this apocalyptic world. Details, I think, make the story far more realistic.
I kind of like the idea for this. Eerily enough, I could totally see the government doing something like this, and the products of such an experiment leaking to the public. We do have horrible things like bombs, after all. I think that's this story's biggest strength; that something like this COULD happen.
Ah, my eyes hurt. >.< I need to stop reading stuff for a bit.
Keep on writing.

Okay, this was an intriguing concept and rather well written as well. I really enjoyed the descriptions. What I'd like to point out is at the beginning a couple of your sentences changed from past tense to present tense so watch out for that in future stories. Also, if you'd like to have Fate as a character then you should probably capitalize Fate every time. Anyway, I liked this story and look forward to seeing more from you in the future.

Danielle Thamasa

Before I say anything else, this is brilliant: the premise and the execution are both great. I'm saying that now (and faving it) so you know I think that while I point out everything I found that wasn't great. Okay? Here we go.

Style/Matters of taste (all subjective, mind you):

[I let the wind tickle... slipping away.] Grammatically correct... but clumsy as well, IMO. “As I closed my eyes and let my thoughts” seems to sound better.

[His teeth gritted slightly, even shaking] This feels clumsy to me: to my ear, “He grit his teeth, his entire jaw shaking with the spasms” sounds better, even if it's longer.

[as my hands turned white from how hard I clenched it] “From the strength of my grip” sounds better here, I think.

[pulling the trigger in my panic, which would get me killed] Completely as a matter of taste, I think the last five words would have more impact if they were set apart in a sentence of their own: “That would get me killed.” It's perfectly correct grammatically; this is just my opinion.

[loathed with all I had to go through this experience again] “Loathed going through this again with all I had” flows better.

[fear written on his face because of the two of us] Leave it at “fear written on his face”: there's no other reason for him to be afraid. It's okay to imply things rather than state them.

[“You've ruined my life,” I muttered] Okay. 'Said' wouldn't cut it here, but I don't think muttered sounds right either: it's used more where the mutterer doesn't want to be heard, but the boy here does. 'Snapped', 'growled' or 'snarled' might work better than 'muttered': they carry more energy and intent in them.

[The well of life, the ultimate muscle, my heart] I would put 'my heart' first, then have the other two descriptions. 'My heart' is a bit anticlimatic to come third; it's a far less impressive phrase than 'the well of life' or 'the ultimate muscle.'

[the man designated as our target] “Our target” would suffice here.

It seems a little odd to change into present tense then back to past tense in the last two paragraphs, but the use of present tense links it to the beginning and ties the entire story together, so I think it's a very good idea. I would leave the second-last as it is and change the last paragraph to present tense.

“Eh?”:

[saw a long extension...could not tell what it was] He could make out a crooked nose and icy-blue eyes from his distance, though: how can he not see a metal blade coming from the man's wrist? If it were hidden by the man's sleeve of body, this would be more plausible.

[turned towards the room I was in] How do you turn towards something that's all around you?

[sight that would fuel my nightmares for weeks] Weeks after he dies?

General:

The first paragraph is really good: it's an effective hook, and the change of tense in the next paragraph doesn't jar (for me, anyway). However, I would either cut, rewrite in past tense, or relocate the first sentence of the next paragraph. The change of tense did jar there, since that sentence is the only one in present tene.

The summary of everything that's happened to the world and the effects of the drug is nicely succinct: it doesn't drag the narative down. Giving only the bare facts is a good way to handle the exposition here, since details would over-lengthen it and slow down the pace of the story. Jumping into the story and leaving the background for a little while was a good idea too. As far as this aspect of worldbuilding goes, you did really well. Nice.

The MC feels like he didn't get enough attention. I have his backstory, and the matter-of-fact way he describes the history of the world is a good indication of how numbed he is to his reality (and how long it's been his reality). Beyond being a twelve-year-old boy, though, there's not a lot of information given about him: there's no defining characteristic tht makes me think he's unique. I know it's hard to provide personal details in a first-person story, but it's still best to do the best you can at it. (I know: it's harder to write about a character from scratch: I'm from FFn too. It's worth the effort, though.)

When he meets the Stranger on the roof, their conversation feels a little rushed. I can't bring myself to believe that after however long he's been on his own, having to kill people just to stay alive, and suspecting everyone around him of having hostile intentions, he would trust someone who he knew was using those drugs so easily. A little more insight into his thought process would make this more plausible. I found the same problem existed when he made the decision to take the drug.

The part where he and the Stranger are fighting their way through the building is really well-paced. I was surprised at how long it was when I looked back over it to write the review, because it felt a lot shorter: it pulled me along like a good climax should. Nicely done there.

You use a lot of dialogue tags where you don't need to: 'said' is normally perfectly fine if all you want to do is indicate who's speaking. It's an invisible word (along with asked): no-one notices it in the text. Most of the time the manner of speech is made clear from the context and the remainder of the time, a strong verb will do better than an adverb with a weak verb. 'Spat', 'roared' and 'lied' are strong tags I saw in this piece. For the others (especially 'stated', 'inquired' and 'questioned') 'said' and 'asked' are fine. (The stagnancy of form that comes from using them is what you want to avoid. It can be just as good, most of the time, to indicate who's speaking another way, by mentioning them in the same paragraph or simply letting it be implied by context.)

Huzzah! I've exhausted myself. I hope I didn't come over as too critical, because I really do think this is good. (I hope I didn't come over as neurotic, actually. -.-) And... I apologise for the length of this. I swear I've written stories shorter than this review... sorry again. Hope to see more from you! (Finally... what, exactly, is flash fiction? It sounds like fun.)

-Sagewolf out-

Damn, this was really crazy son. I mean, this was great story my friend and I would love to see a sequel to this. It actually gave me inspiration for the Spade Series but I won't say how. Nice story man!

Excellent one shot! Seriously Awesome!
If you ask me, you could totally expand this and make it into a full length story!!
It has a lot of description and doesn't really get boring.
I think you did very well!
Keep up the writing because it is great! No lie!