I played as a human hero and completed the map in 58 days (I got the Thunderlord as a reward). At first, it was difficult and reminded me of "Uninvited Guests," but then it got easier. As I understand it, at the beginning, you need to increase defense up to the base defense penetration and luck, and most importantly, increase attack. Otherwise, it's very difficult to counter buffed Barbarians (I even had to restart). Regarding the Sphinx, I'm not sure, but the castles are indeed very close to the center (3 days' travel). Overall, thank you to the author for the map.