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