Here is the full list of all 32 Röki achievements.
Return Trollhilde's gold
Acquire all other badges
Get to know the castle's inhabitants
Complete the game
Say everything that needs to be said
Find all of the castle explorer's notes
Open the gate to the tower
Solve the sundial puzzle
Solve the dining hall puzzle
Find all the Guardian banners in the castle
Complete Chapter 2
Examine 50 unique backpack items
Insult Shroomi
See beyond the veil
Awaken Jötunúlfur
Find all of the petrified Trollbrothers
Awaken Jötunbjørn
Have Fossegrim charm an instrument
Escape from the waterlogged caves
Open all of the Rootways
Create a new path in the church
Activate the ice altar
Get to know the mill Tomte
Summon a Tomte
Rescue the Great Mother Tree
Read every gravestone
Spin the top 5 times
Help a troll
Explore off the beaten track
Complete Chapter 1
Escort Lars to the outhouse
Successfully combine two items