With no page count it might be hard to determine the levels. There might be a free supplement thing put out for level 1-3 to introduce some things and then a level 4-12 book or something.
Although what level do I need to be fighting a death tyrants and pig-faced demon? And the lich Tam guy? What is that movie thing we throw around Schrodinger's Gun, or am I mixing up the cat? You do not show me powerful liches and demons and then do not put them in the book to fight. Does the party need to be 20th level for this?