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