Number six in my "Discworld Read-Along" with my husband.
I was really enjoying it until the end, when everything felt rushed. From Albert's reveal on, there wasn't really anything organic. The "subtext" in the last fight was so heavy handed, an infant could have grasped it, and the romance was non-existent until the last dozen pages.
I didn't understand Death's domain, either. Is there only one portal to warp to? I don't think so, because they winked out over Sto Lat at the end, but Death seems to generally appear around Ankh-Morpork. So, do the Duty. Warp home. Warp to the second place. Warp home. Warp to Sto Lat. Rescue the princess like 6 hours earlier. Everyone have tea.
I liked the plot idea of Death's apprentice, but it didn't come together.