There are challenges.
Each targeted attack or ruined monster body part should mean something. The problem is the monster variety. CDDA monsters can be quite different in nature, although many of them are bipedal (human-like). But then again, DF has even greater monster variety.
CDDA monsters currently don’t have anatomy like the player. They just have generic hitpoints. So the first gargantuan task would be to carefully define their body parts and their hitpoints. Or, we could give them classifications such as ‘bipedal’, and then define the characteristics (anatomy) of a bipedal. After that, one would have to think how the loss of a body part should affect the monster, or how the various combinations of lost (destroyed) body parts should affect.
Designing each creature’s bone structure is another potential major task.
There are at least two types of beings - the living (NPCs, animals) and the undead (zombies). So basically one might have to recreate the DF anatomies for the living. Zombie anatomy would probably be far simpler or less interconnected. Zombies probably don’t have much use for internal organs, with the exception of the brain, which is traditionally their only weak spot. But I guess internal organs could and even should be added to them anyway. Who knows what function they might serve outside the body, if not inside.
Bipedal zombies that would lose either leg should become their crawling versions. Currently we have only crawling zombie, which is its own monster and not connected to regular zombies. Decayed zombie should become crawling decayed zombie. Zombie hulk should become crawling zombie hulk… if for whatever reason it ever loses one of its massive legs. If it were up to me, it’d actually hop around faster with the remaining leg than run with two, taking giant leaps :D. So, we might have to add each creature’s crawling version - not necessary but just a thought. I mean, if we have these mutilated zombies mixed with the intact zombies, they should be visually represented, but if they’re not… is that OK?
If one were to start working on adding anatomy, I guess it’d be wisest to start with the bipedal zombies, them being the most common. Detailed anatomy creatures would have to be able to coexist with non-anatomical creatures, because this work would not be done in a day.