Here is the full list of all 28 FrostRunner achievements. It takes around 1-2 hours to unlock all of the achievements on Windows.
Get the Gun
Get the fast time on all levels
Obtain all collectibles
Get the fast time on all levels in Chapter 4 - Fling
Obtain 20 unique collectibles
Get the fast time on all levels in Chapter 3 - Tether
Collect the Sword
Get the fast time on all levels in Chapter 2 - Ice
Collect the Frog
Obtain 10 unique collectibles
Get the fast time on all Prologue levels
View the Credits
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Finished Chapter 5 - Chain
Get the fast time on all levels in Chapter 5 - Chain
Finished Chapter 4 - Fling
Used fling for the first time
Finished Chapter 3 - Tether
Tethered for the first time
Finished Chapter 2 - Ice
Finished Chapter 1 - Ring
Get the fast time on all levels in Chapter 1 - Ring
Finished the Prologue
Found a collectible
Died for the first time
Jumped for the first time - Feel proud!
Obtain an achievement...see what we did there?
Took your first steps