Here is the full list of all 30 The Legend of Korra achievements. It takes around 15-20 hours to unlock all of the achievements on Windows.
Completed all tutorials.
Collected 10 cabbages.
Collected every treasure item.
Spirit-bended 200 dark spirits.
Completed the game on Extreme difficulty.
Purchased 12 talismans.
Completed a Naga Running sequence without hitting anything.
Performed 100 Finishing Moves.
Went into Avatar State 10 times.
Completed Chapter 1.
Completed the highest difficulty of Pro-bending.
Won a Face-Off in a Pro-bending match.
Got 10 Knockouts in Pro-bending matches.
Maxed out all bending types.
Completed Chapter 2.
Completed Chapter 8.
Completed Chapter 7.
Countered 100 times.
Obtained all combos.
Completed Chapter 6.
Dodged 100 times.
Entered the Collection Screen for the first time after finding a treasure.
Completed Chapter 5.
Used your first equipped item.
Completed Chapter 4.
Went into Clash Mode 10 times.
Jumped 100 times.
Completed Chapter 3.
Equip your first item in Korra's Room.
Bought your first item at the shop.