Here's what I know at the moment:
- Players portray non-traditional fantasy RPG characters like tinkers and bakers. They are not adventurers.
- Every character is hit by wanderlust (this is a normal and expected part of the setting) once during their lives. A game of Ryuutama covers the travels of a group who get wanderlust at the same time
- Wilderness travel is a big thing in the game (which situates Ryuutama near games like The One Ring and -- I think -- Chuubo's Marvelous Wish-Granting Engine)
- The GM portrays a dragon who looks after the travellers
- There are four different types of dragon a GM can control. A ... Winter (?) Dragon is one that signals a dying world.
I'll post my thoughts in the comments as I get a chance to read the game. Which, by the way, looks beautiful and (on an initial skim) clearly-written and logically-presented.