Here is the full list of all 13 Empty Horizons achievements. It takes around 0-1 hour to unlock all of the achievements on Windows.
Mireille begins her journey.
Mireille ends her journey.
Mireille recalls her first love.
Mireille (finally) gets a choice.
Mireille heads out into the great unknown.
Mireille reunites with Lyon.
Mireille gets her revenge.
Mireille and Lyon bond.
Mireille braids Lyon's hair, as you do.
Mireille indulges herself, despite the shame.
Haven't you been here before?
Mireille gets treated like a princess... for five seconds.
Mireille ponders in the bathtub.