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