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