The track itself is pretty good actually. Especially the percussion.
The song structure is really good and I loved how the flutes came in.
If you want a more post-apocalyptic feel I would recommend messing a bit more around with reverb effects. Try to use different reverb vst plugins like "Valhalla" or "it's a space odessy"
(I'm pretty sure the latter is free).
Also you might also want either a female choir or a higher pitched choir. For me it gives me more of an wasteland and apocalyptic feel with a higher pitched choir.
You could also try putting the choir some octaves up.
Only reason I won't give3 you a full score is because I think the instruments need a bit more reverb and a bit more "spacey" feeling.
4.5 stars from me.