Great stuff for this fix.
With regard to the undead, hit-points, etc.:
An approximation of health for all creatures is sensible when you consider the systemic stress and toxicity related effects of cumulative injuries. (See also, crush syndrome, exhaustion related death, etc.) Rather than breaking with the simulation, a hit-point system actually meshes nicely with it when you're considering effects that are too small, too numerous, or too complex to simulate exactly. In living creatures, having minor injuries cause a buildup of a nameless, non-transmissible poison that damages organs might be the best way to simulate that, but the effects wouldn't be much different in practice than an H.P. meter that goes down with any injuries dealt and returns with bed rest.
On top of that, just like now, an H.P. system can be extended to other types of creatures and in other roles. For entities that are made up of a singular body part (blobs, etc.), ones that are animated by some otherworldly and unknowable force (metal men, etc.) and the undead in particular, this is more or less necessary since normal biology simply doesn't apply to them. Being able to 'break' them is the most sensible way of doing this unless you assign them a material or body part that keeps them moving. (In some cases this could be made fluffy. Talismans, magical symbols, a material layer made out of writhing ethereal worms, and so forth could be the animating bits of these creatures.) I strongly suggest that H.P. be made a more permanent feature of the game at least until these kinds of fantastical things are given due polish, and also for the reasons explained above.
Excellent work with this release so far. Looking forward to the next while of updates.