Humanoid Constructs and Undead ARE NOT immune to critical hits. Any humanoid creature needs to remain intact in order to function at 100%. Creatures with regeneration still require time to heal. Any humanoid type that walks and looses a leg is crippled until that leg is regrown, reattached or whatever…
Soulless creatures like constructs and undead may not be living but their magical animation requires a physical form. In most cases whatever consciousness or awareness they had will seemingly ceases to exist when their body is utterly destroyed. Similarly when their body is damaged it must still be reassembled, repaired, or regrown before their body functions are fully restored.Constructs have no former living memory or soul. They only “live” as long as the enchanted parts they are made of exist. They can only sense, reason, react, feel, move, think, or otherwise respond when their “parts” are connected to each other. In this sense they are like a living creature because the function of their parts is contingent on four things:
- -Their parts must remain attached to the body.
- -Their parts must remain whole and mostly undamaged.
- -The function of individual parts is contingent on the overall “health” of the construct.
- -Their parts will not repair themselves nor will they function again until they are repaired.
It’s easiest to think of humanoid constructs as having limbs and organs (including sensory organs) that require magical blood to function. A construct may not have a heart or lungs but it needs a chest. A construct may not have a brain, but it needs a head… etc. etc. If you damage a construct to zero hit points it is no longer conscious. If you damage a construct to -10 hp’s it cannot be repaired it must be reanimated. Constructs do not loose hp’s from bleeding however.
It may seem unreasonable to think that humanoid constructs are made to be vulnerable in many of the same ways as a living humanoid is; or that their “memories” and consciousness can possibly be restored to them after death but I think all PC’s should share certain “realities.” lol.