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.
Went into Avatar State 10 times.
Purchased 12 talismans.
Spirit-bended 200 dark spirits.
Completed the highest difficulty of Pro-bending.
Completed the game on Extreme difficulty.
Performed 100 Finishing Moves.
Maxed out all bending types.
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 Chapter 7.
Completed Chapter 6.
Dodged 100 times.
Completed Chapter 5.
Went into Clash Mode 10 times.
Entered the Collection Screen for the first time after finding a treasure.
Completed Chapter 4.
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.
Jumped 100 times.
Completed Chapter 1.