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