Anyone who wears a face-obscuring garment is a member of the Evil Army.
The villain has trouble telling specific minions apart.
Zig Zagged: Some of the enemy forces are wearing masks, whether for intimidation, protection (armored helmets or gas masks), or both. The regular grunts don't, to humanize the forces a bit. In a video game, this is done to denote who's elite and who's going to die from two bullets.
The young hero Albert kills several of Emperor Evulz' forces while under the impression that they're just faceless, mindless monsters. However, when he comes across a wounded soldier who removed his mask, he realizes the truth and has a Heroic BSOD.
The mooks complain about the masks being unwieldy, stifling, and hard to see through.
The unmasked solider, Vincent, turns out to a family member of Albert, who after a while recovers his memories and tells Albert that Evulz Brainwashed Vincent into a Faceless Goon, so that Albert would have a Heroic BSOD.
... But the mooks survive several shotgun rounds to the face thanks to their armored masks.
Albert decides that just because they're people, doesn't mean they aren't evil, and that he can't still beat the crap out of them, provided they live.
Played For Laughs: Not even the soldiers can tell each other apart when they're suited up.