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