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