I agree with the answer you've chosen as the best answer TC, but I'd also like to talk up the world's charm as well. I played it on the GC about 5 years ago.
What I liked so much about Beyond Good and Evil was that the character relations seemed so authentic. The game starts out in an orphanage where the two characters Jade (human woman) and Pey'j (pig man) looks after young children of many different races that have had their parents pass away due to the antagonists (the Domz) attacks on the planet. So it starts immediately grabbed me due to this noble sort of motivations from the main characters. After that, it becomes more about the conspiracy around who the Domz really are.
I'd agree with the claims that the game-play being monotonous in terms of puzzle solving and stealth. (See this ol' one by none other than Jeff Gerstmann, http://www.gamespot.com/reviews/beyond-good-and-evil-review/1900-6085013/).
In closing, it was a varied game with sub-par, forgettable game-play (that controlled well) that also had a deeply interesting narrative with characters that acted in a way that was more multi-dimensional than typical video game protagonists.