Most amusing part of the game is breaking it.
Avatar is an easy 1000 Gamerscore an notorious for it, the funny thing is the game past the opening scene is so much worse but so few gamers have actually seen it. While you can easily tell from earning the achievements that the main characters attacks do little damage, the equivalent of blowing air on someone.
The enemy AI though can be pretty damaging when not being stupid. To be fair the boss characters actually will attack you right away and usually constantly. Regular enemies though are the best to mess with, they will sometimes follow the Airbender around for a full minute before striking once. Its even possible to herd an entire stages enemy spawn in the sewer level to the end, they actually follow you through checkpoint areas.
Avatar's name will forever be stained among those that own Xbox 360's and with the developing care put into this game it kind of deserves it. I especially love the side quests, some can be finished while others never trigger a quest complete scenario. And the reward? Usually nothing.
Verdict: Rent for Gamerscore only, do not pass Stage 1 for sanity sake