The story-in-a-story structure dilutes it. Particularly the part where we are introduced to Victor and told how they first met. Ask yourself what you are trying to accomplish with that introduction and the conclusion. It feels to me like noise that draws the reader away from the 'confession,' which is, in my opinion, the only interesting part.

How would I fix this story?

I would make Victor's confession the primary focus and remove everything else: the purple prose about the well-lit basement. The fact that they are high. The little aside about how they met by breaking into a truck. All of Roy's little interruptions (what the, that is disgusting, you're full of shit). They are all irrelevant distractions. Get rid of them.

If you really want a narrator, don't spotlight him. Here is a famous example of a story-within-a-story. Notice that Twain does not weigh us down with a lot of history about the person who narrates the story. Really, the narrator is not important. It is the story that is important. Mark Twain sets the stage by explaining where they are--a tavern--and describes Wheeler very briefly before moving onto the main event. Less is more. Let the story itself take center stage.

Also. In Thomas Pynchon's anthology of early short stories, Slow Learner, he said one of his biggest missteps as a writer was trying to show off his ear for accents before he had acquired an ear for accents. I think you also are overstepping your ear. Nothing will make a reader cringe as much as a poorly-written accent. On the other hand, no reader has ever read something and said to themselves, you know, I really think he should have substituted nigger for nigra, or this you know with a y'know, or this creek with a crick. What I mean to say is: nobody has ever cringed at a word that was spelled the way it appears in the dictionary. If I were you, I would scrub all the colloquialisms from this piece of work.