Here is the full list of all 31 Mountain achievements. It takes around 200 hours to unlock all of the achievements on Windows.
Mountain lives forever
Mountain lives for a long time
Mountain experiences a lot of pain
Mountain experiences pain
Mountain has a lot of alone time
Mountain is bombarded by things
Mountain has some alone time
Mountain cannot stop thinking
Mountain thinks quite a lot
Mountain goes on dying
Mountain dies several times
Mountain experiences death
Mountain thinks it is invincible
Mountain sees it all come and go
Mountain is alive for a short time
Mountain watches the days go by
Mountain keeps surviving death
Mountain survives death
Mountain plays a lot of music
Mountain keeps organizing itself
Mountain makes it unrain
Mountain is home to many things
Mountain organizes itself
Mountain thinks
Mountain sings quite a lot
Mountain sings
Mountain is home to something new
Mountain no longer trusts the weather
Mountain cannot predict the weather
Mountain plays music
Mountain has unusual weather