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 fast time on all levels
Get the Gun
Obtain all collectibles
Collect the Sword
Collect the Frog
View the Credits
Get the fast time on all levels in Chapter 5 - Chain
Get the fast time on all levels in Chapter 4 - Fling
Obtain 20 unique collectibles
Get the fast time on all levels in Chapter 2 - Ice
Obtain 10 unique collectibles
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Finished Chapter 5 - Chain
Finished Chapter 4 - Fling
Used fling for the first time
Get the fast time on all levels in Chapter 3 - Tether
Finished Chapter 3 - Tether
Tethered for the first time
Finished Chapter 2 - Ice
Get the fast time on all levels in Chapter 1 - Ring
Finished Chapter 1 - Ring
Finished the Prologue
Get the fast time on all Prologue levels
Died for the first time
Found a collectible
Jumped for the first time - Feel proud!
Obtain an achievement...see what we did there?
Took your first steps