Headcrabs. Those forgeters are resilient.
A headcrab is incapable of taking a single .357 round to the face. Let's compare this to weaponry found in the respective universes of everything else on that list:
An M6G from Halo chambers 12.7x40mm (.50 cal) HE rounds, meaning headcrabs will die if that gun so much as farts in their general direction.
Assuming an Autogun has a 7.62 caliber, an a cyclic rate of fire of 625 rounds per minute, that would easily put it significantly past the amount of firepower a .357 revolver would put out, so 40K wins out there too.
Speaking of 40K: A lasgun is capable of penetrating up to a meter of concrete and is one of the most common weapons in the galaxy.
The C-14 assault rifle from Starcraft, the standard Terran armament, chambers 8mm hypersonic bolts. This weapon is capable of a fire-rate of 1,800 rounds per minute, and can penetrate up to two inches of solid steel.
The M41A pulse rifle is chambered in 10x24mm caseless and possesses a fire rate of 900 rounds per minute.
Literally all of these weapons could grab a headcrab by the claws and faceforget it so hard it would be incapable of swallowing without a tube and you call it "resilient"?