Oct 29, 2021: Just completed the newest installmemt, The Sultan's Inventor. I have played and enjoyed all the Adventure Escape Mysteries, from the first individually packaged apps through the most recent update to this package.. The pricing is very generous. Ads only appear between chapters, and a key (to access a chapter) is generated by passage of time (every 3 hours, I think, with a maximum of 2 keys accumulated. I buy addtional keys on occasion to pay the developer.