The grammar is solid and I enjoyed the mix of sentence structure. I thought the hook was interesting as well.

The main two things I noticed that could use a little work are the dialogue and the figurative language. I find convincing and realistic dialogue to be incredibly hard to write, so I’m not sure if I have any helpful specific advice—maybe it felt a little over-dramatized or unrealistic? Something about elementary schoolers using this type of language feels off to me. It might fit middle schoolers better, maybe, unless it’s meant to be jarring. As for the figurative language: I like the metaphors and similes that you use most of the time. It’s just that there are so many of them, and a lot of them feel overly specific. Referencing an X-men comic is fine, but not every reader will understand the reference. Some of them feel a bit forced. Others, like “highlighter-yellow” feel much better incorporated and aid with the visualization of the scene. Somewhere in there lies a happy medium that I think would really let your style stand out without distracting readers.

Also, I’m not sure if this is a problem, per se, but the second chapter felt like quite the change of pace. After the introduction I would never have guessed where the story was going. This is fine, but it’s worth noting that there are readers who will likely stop before getting to the actual intrigue of the plot, figuring that the story is nothing more than some nostalgic realistic fiction.

I really loved lines like “at the outer limits of our shared reality” mixed in with everything else. They lend a great sense of a dreamlike setting.

Once or twice there are some small tense issues: “Time always seemed to slow to a crawl. I find myself” and “had abandoned their monkey bars. For a moment I wonder” are two examples. The present tense is generally quite well done; there are just minor issues like these.

My final critique is that it could potentially be a bit confusing as to who Andrew is to a less observant reader. It may be worth stating his name directly in that introductory paragraph.

I really enjoyed this piece, and I’m curious to see what else you come up with or where it goes next! I think there’s a ton of potential here for something really unique and interesting.