Liminality At The Park

[Johicopter]

The ball court’s rusted hoops, stooped 
under the weight of dusk, watch the moon-
cloud shadows swoop across concrete.

Nearby, in the dark, children launch 
screams from park swings and flail, awkward  So they scream from the park swings? If that's what you mean then that's fine, but it confused me for a second because the sentence also makes sense without "screams"
as mid-flight moth wings, before pinpoint landings. "Children flail before landings" feels a little awkward to me. Maybe flail into landings?

Underneath the pagoda, teens smoke marijuana
and the skunky aroma wafts strong as their coughs
across the trail where the wind picks up over the stream.  This is the only line in the poem where there is no obvious assonance or feeling of "flow" (see general comment below). It stood out to me as it kind of halted my rhythm of reading through the poem.

Deer in the low grass stare, heads turned,
white tails bare, until I’ve stepped too near
and they zip away quicker than sparks disappear.  This comparison leaves me wanting more. You could end it with "zip away" and the visual would be the same. Also perhaps to me, the metaphor seems to lose its power if you are just going to use the word "disappear" anyway.

I really like the imagery here and I especially liked the way you grouped words with similar sounds together, i.e. "hoops" and "stooped" and "pagoda," "marijuana," and "aroma." It creates a really interesting, near-rhyming effect that is especially fun to chew on when the poem is read aloud and keeps the momentum of the poem going.

In terms of the last stanza, I have two main interpretations:
A) This is simply a fourth vignette in this park nighttime scene. If this is the case, I would relate it spatially to the other three stanzas. Are they across the stream? Do the deer hear the screaming children?
B) It is a metaphor for all of the other observations. The narrator observes the kids and the teenagers but they can't get too close because they are worried that they might spoil the scene, like how one watches deer from afar. In this case, the last stanza can be read as having a message about observing and appreciating from a distance so as not to tamper with the "spark" of the scenes one is witnessing, which I find fascinating, especially if it wasn't totally the intention. This is my theory for why "I" is not introduced until this last stanza. I appreciate the ambiguity of interpretation and don't wan't to ruin it, but if this interpretation is the case, I might suggest doing more to break up the pattern of [location] [subject] [verb] in the first line of all of the stanzas except the first one. This would separate it slightly and make a shift to a more metaphorical place clearer.

Again, very good poem, love the imagery.