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