Well, it’s certainly in space, and you’ve used a bunch of obvious Western tropes… but, for all that, it doesn’t really hang together.

Also, I’m afraid I really dislike this sentence: How he got his powder to strike at 280 Kelvin in 10 millibars of CO2 remained a mystery.

You’re slapping your reader around the face with facts, where what I suspect what you wanted to do was offer a humourous nod to the impracticality of a weapon designed for Earth temperatures and pressures in a completely different, and much more hostile environment.

As it stands, what you’ve done, is break the fictional aspect and point out to your reader why they shouldn’t suspend their disbelief.

Fair comments. I was hoping to enhance the mystery around this larger-than-life character.

The only way to improve this piece would be to spend a lot longer on it than I did. The lesson, I guess, is that you get out what you put in…