Funnily enought the first section to be cleared on my replay. The map is at 91% exploration and I have almost got all the Crimson Agates so not quite 100% completion but I did the main quest before the world level went up for the tons of primogens.

This was the first and only new area added to Mondstat and introduced the freezing mechaninc to the game. There was an event tied to this which is gone now but it added Albedo and Ganyu so that is very nice. Overall for an early content release this was very nice as I don't think there was anything new to explore until the Chasm which was quite far away in terms of time before updates.

Update (Mastered):
100% achieved and all side quests finished up now. I can say now the verticality of the area has kind of gotten to me with the mix of sheer cold made exploration a pain at times. Still I would say for early game this a good area to explore due to the higher primogen count in chests in comparison to the rest of Mondstat. It's probably one of the better updates to come out during the 1.0-1.6.