It's the typical platform game: Simple, beautiful, pleasing to a casual gamer, and absolutely plotless.
It's a platform game, pure and simple. It's like Super Mario, only it's 3D. The few RPG elements, such as character growth and equipable items, fail to produce any feeling of satisfaction the mentioned genre is so famous for. The equipable items will not be visible. Putting on a Heavenly band will not change your look, nor will putting on a diferent robe. It changes your stats, nothing else. As far as the character growth is concerned, it is limited to choosing wich moves he'll learn next, if you don't want to let the game do that for you (which, after a while, I did, considering I couldn't really care that much about them).
This game's greatest flaw, however, is the complete lack of a decent plot threading the missions together. 90% of the time, you'll reach a city at the center of the scenario, talk to its elder, and while he gathers info on the scenario's plot (for lack of a better word), you'll wander around doing missions for the in game characters. In fact, these missions are horribly repetitive, so much that the location of its solution is usually one of the 4 corners of the map. Hell, the dialogues are so limited, that the only thing actually driving you forward in this game is a green arrow by the edge of the minimap. There isn't a single charismatic character (including your own), and the boss fights, as pleasing as some might be, are usually against a big mean man you've never once heard of in the scenario.
Still, the graphics and overall sound are simply great. You will wonder about jungles, ice tundras, and huge metropolis with a bit of an awe (despite being easy to get lost in). And the songs and voice actings are well made, even though less than 10% of the in-game dialogues are voiced.
From a game based on a TV series (or a movie, as far as that is concerned) you should expect two things: 1-That it will please the fans of the series, something that I believe this game will; 2-That will make people that aren't really that familiar with the franchise to become interested, and here is where the game drastically fails. There's nothing to atract people into the Avatar world... The premise of Elemental powers, and warring countries is great, but this is only touched in a shallowed manner by this game.
I haven't played the first game, but the least you can expect from a title is that it stands on its own, without relying on it's TV genitor (if that's the case) or its predecessor. Avatar: Burning Earth, fails to deliver on the primest of principles.