As far as action goes, the game would have been a button-mashing snooze if it weren't for the cool level up system that gives characters special two button combo moves as they gain experience. These special moves can be used strategically to dispose of enemies more quickly, and help to alleviate the repetitiveness of the hack 'n slash action.
The problem is that each character only has a total of four special moves, and they are given out too early in the game. After each character levels up only a few times, all four moves will be unlocked, and from there it was easy for us to pick our favorite, strongest move for each character, and repetitively use it to cut through all our opponents.
Each of the four playable characters is supposed to have his or her own strengths and weaknesses: Aang can use special Airbending moves to damage opponents, Haru can use Earthbending powers, Sokka has a boomerang for ranged attacks and is great for general combat, and Katara has healing powers.
Ideally, having to weigh the strength and weaknesses of each character in battle would add some depth and strategy to the gameplay, but it falls flat here because most of the characters perform more or less the same, and they all level up regardless of who you choose to control. After testing them all out, we found ourselves primarily playing with Aang, and only switching to Katara when the party needed healing. Because of this, having four different playable characters seemed kind of pointless here.