Visually, the game looks okay, but I have to say I was somewhat disappointed to find it didn't fit the same style of the previous game. Instead, we have something that feels very much like a generic 3D action game that just happens to follow the plot of an animated series. While the graphics themselves aren't particularly bland, there isn't really anything about them that makes them stand out. The last game had a very different feel to it and the isometric, but still 3D environment, really helped to make the game stand out in my eyes.
I also have mixed feelings about the game's sound. Both the music and the voicework are lifted straight out of the series. While I felt like this was a good thing for the music, and really gave it that Avatar feel, there is no additional dialogue, so everything said in the game comes from the show and only the show. Consequently, I didn't feel like I was getting anything extra out of the game that I didn't see in the show, unlike the DS version which went into a lot more detail and felt larger.
There is one other thing that I have to mention with regards to graphics and sound, and that's lip synching. Some games handle it well and the lips are dead on, others don't quite have it right but at least try, The Burning Earth simply keeps the characters' mouths closed throughout the conversation, but still has their heads bobbing around as if they are talking. It was an odd experience, and even odder when the models would suddenly move their lips for one or two lines in the dialogue. This part just helped to give the game its somewhat unfinished feel.