One thing of mention is the undead templates changed from 3.5 and the new Ectoplasm creatures exists.
The changes in the templates let the undead keep SLAs (now under Spell Like Abilities, rather than any category lost by the template) and fast healing/regeneration (under HP, and you only lose the unrelated hit die from that section). Zombies also now only need a physical body (I assume this means anything other than incorporeal and elementals are valid. This bizarrely allows construct zombies). On the down side, undead are squishier, lose immunities and the classic hydra zombie no longer works (It has real pounce instead of a special quality that allows it to attack with all heads as a standard action, which is lost).
Ectoplasm creatures keep special attacks, can air walk and have pseudo intangibility, though there is no way to create them.
