He's done an especially nice job with the setting; a single word or short phrase here and there, and you know right where (and when) you're at. Pacing, flow, characterization and dialog are all very good.
I have a personal problem with the primary plot mechanism, the drug. My suspension of disbelief isn't willing enough to swallow that pill (begging your pardon).
Aside from that, I really did enjoy it, and this is still a very well-written story.
The only mechanical problem that stuck out at me was
Looks like an errant paragraph return; no biggie. And, I'd have italicized the internal monolog."Crouching in the ruins of the dead city Popeye listened to the wind blowing from Kaol, a few hundred haads to the East and the roars of the ba'aths, the great hunting lions of
Barsoom." If you are going to plagiarize Edgar Rice Burroughs, at least get the names of his characters straight, I mused sourly. It's banth, not ba'ath, you mediocre hack.
Good job!