Despite the low number of reviews, I would say Namhansanseong is covered pretty well by its earlier visitors, and I don't have all that much to add. In June 2023, I came the same way everyone seems to come (including all the elderly hikers that filled the bus to the brim) and walked the commonly covered stretch between the Northern Gate and Western Command Post, and short of a couple of highlights, the overall experience seems to be the same for everyone. This is a mountain fortress, nothing more and nothing less. It's honestly an impressive one at that; for its size and the terrain it covers, Namhansanseong was definitely no easy feat. That being said, you'll mostly be admiring the views and the nature much more often than the structures of the actual fortress. I found the gates and command posts in Hwaseong to be more impressive and better preserved. The Northern Gate seemed to be under renovation, sadly, but I did see the Western Gate, Cheongryangdan Shaman Shrine, the Western Command Post (probably the most impressive and important structure), and Gukcheongsa Temple, as well as the Emergency Palace. Most of my nearly 2-hour visit was walking, as the terrain definitely slows one down - the hike from the central roundabout up to the northwestern fortress walls is quite steep. To me, the best part of the visit was the Yeonjubong Outwork, culminating in the watchtower at Yeonjubong Peak (picture attached). From here, you have an incredible view of both Seoul and the mountains, especially Namhansan, which is clearly ringed by this vast fortress's walls. It just puts into perspective the scale of this project, all to make an emergency capital city for the Joseon state. While this, to me, isn't the greatest fortification in Korea, it's hard to deny its OUV. That being said, I wouldn't recommend a visit here to a casual visitor unless they loved hiking; the less mobile would see next to nothing here, and the site is quite a hassle to get to, especially on the afternoon we visited as the bus from the subway station (already an hour from central Seoul) took nearly an hour due to traffic on the mountain, so I'd more likely recommend Hwaseong instead. Otherwise, this is a great place for hikers, history buffs, and WHS collectors. Oh, and I heard there's a restaurant near the roundabout that serves up a mean octopus & scallion pancake!