Here is the full list of all 16 Sole Iron Tail achievements.
Complete the full scarf in the tutorial stage for Tuto the Penguin
Complete the full scarf in the daytime snow stage for Polaris the Polar Bear
Complete the full scarf in the sea stage for Pawleal The Seal-er... Walrus
Hit Pinky after waiting 30 seconds
Complete the full scarf in the whale stage for Parfeth the Bird!
Complete the full scarf in Soul Iron for Lily the Spirit Guide!
Beat the final boss of Sole Iron Tail
Reach the end of Sole Iron Tail
Collect the full scarves for all levels and reach the end.
Collect all big scarves in each level.
Achieve 100% progress in the story mode
Achieve all badges for each level in story mode.
Play through each level in time trials!
Dont charge out of the snow mound for 1 minute
Bounce on bombs three times without touching the water/ground.
In Sleeping Giant, get to the top off-screen section of the first cave.