Only Sasuke could claim to walk up a mountain and not notice it was there. *grin*


A lot of my comments are little grammar things:

Despite what people may think at the present moment Sasuke was not an idiot.
"Might" instead of "may" would maybe keep the tenses from switching from present to past?

Going with the Sound Nin was not the best idea in his twelve years of life, but things were a bit blurred at the time. There was a lots of anger, a lots of frustration, and just a bit too much fear because Sasuke knew that one more inch and Naruto would not have stood up again.
I think I would use "leaving" or "departing" or something to that effect with "with the Sound Nin," but that might be just because down here, 'going' is a euphamism for dating (though I like the thought of the Sound's Four becoming Sasuke's harem *grin*). Also, it only needs to be "a lot" instead of "a lots."

Leaving Naruto on the rocky ground bleeding like a pig and the trek into the dark forest....
I think "trekking" instead of "the trek" would make the sentence run smoother.

Sasuke does not think he was in his right mind....
You've been using the past tense in the last few sentences, but here you suddenly switched to the present. Maybe "did not" instead of "does not"?