I changed it up a bit.
Only problem is that return of the living dead zombies never die. Ever.Your unliving ogre has 24hp and isn't destroyed until -24. A Ogre Zombie has 55hp and isn't destroyed until 0. Notice its more or less exactly the same.
D&D zombies die when they've been chopped up enough. Maybe the head got hacked off. Maybe the torso was eviscerated and then skull was curb stopped. For whatever reason the negative energy keeping the thing animated suddenly ceased to exist.