Very strong writing here! Your prose flows together very solidly, with some really good detail. For example, I liked that he not only killed his first alien on Antiles III, but that he killed the alien "with a wrench", hinting at a lot of other untold stories in his past.
If I had to nitpick, I'd just say you might have benefited from a little more editing (a few places where things weren't capitalized, and some misplaced punctuation). The ending also doesn't really resolve the "not all debts can be repaid" line, but all of this can be chalked up to the constraints of the jam, I'm sure!
Overall, I loved your word choices ("forsaken ball of mud", ""lusting after the reward", etc) and the way you portrayed the downfall of this power-hungry, selfish commander.