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