I think it's because there are "a few exceptions due to the nature of the creature".(lol jkjk) The chest, for example, doesn't have an attack animation but instead has an open/close animation (because it's meant to be your inventory buddy and not an attack buddy). This really is a great pack to an already great collection! Krishna really has made one of (but most likely the) most complete and expansive tilesets on itch.io.