Kurt, a very serious topic; the Vietnam War. Lyrics are lush with visuals and puts you right there in the jungle fight.
I listened to the track 4-5 times, making notes as I listened.
I got a "Ring Around the Rosie" nursery rhyme feel in your intro and chorus which is good because basic and memorable are good things in a tune.

Your title is very good and your hook delivery is great. The hook resonates in part because of the nursery rhyme "All Fall Down" association.
Your vocal suits the tune well. I'd look at some of your phrasing, really minor.

Sonically, I'd add an actual helicopter audio in on the intro to help the listener's mind right in the place you want it.

I think you could edit your lyrics a little. For example:
"I light up a cigarette, then I hear incoming rounds"
Napalm scorches this nightmare "scene" with "hot" sizzling sounds.
Cries of the wounded are making me cringe
I could help but I dig through my bag for another syringe

Great here: "Cremate my memories, cast them all around"
Your bridge is right out of the psychedelic 60s-early 70s and fits well in the tune.
I don't play an instrument just piddle around on the piano but I thought some minors would support the dark, desperate places this tune goes.

Really enjoyed this. Thanks for sharing.

Regards, Emmanuel

http://www.reverbnation.com/emmanuellawrence