Horrifying thought:

I can't see any *physical* reason why recently deceased enemy combatants couldn't, if not too badly damaged to begin with & retrieved before peripheral necrosis progresses, be patched up & made into short-lived meat-robots using computer-controlled electrostimulation of skeletal muscles/diaphragm to move/breathe, glucose pumps to temporarily substitute for the lack of digestion, mechanical pumps to get the blood flowing, &c.

So, computer-controlled zombie shock troops.