I don't understand why people are saying Gravity Rush deserves a 9.0. It's far from great. I'd say the GS review is pretty much spot on... maybe you can bump it up to a 7.0.
Now, I think this game is good, but far from amazing. The whole city with music really adds a lot of character and charm and also I really enjoy the comic book narrative, but other than that, the game falls short on a lot of things. The reason why this game did not score so high because it fails to meet expectations on a lot of things.
a) There arent really any side missions, only challenges. It would have been great to see the traditional side missions (like Arkham City). The developers should have created an environment filled with side characters that are memorable (think GTA). For example: You need to help Old Granny Smith fly from one point to another and after 3 story missions, she needs help getting groceries, and so on (you get the picture). The fact that there was no real side missions made the game less enjoyable and thus will brings me to my next point:
b) The story is short and not engaging. Now I'm not expecting an Oscar worthy story (see Mafia 1) but it wouldn't have been terrible to create memorable characters. Sure the story can be generic (its hard to come up with original stories) but the game could have created characters that had a lot of depth to them. Also the story is somewhat choppy. Like the transitioning is pretty awkward.... for example, Kat is all of sudden in this new world with amnesia and for some reason everything seems to fall in to place and seems to work out just fine. I would have loved to see more shuning of shifters early on in the game and people are giving her a lot of trouble. Also back to the short part, the game is not lengthy. Without any side missions and droaning challenge missions (the challenge missions kept the game going for a little bit longer but at most times you just want to continue on to the story and ignore grinding gems for skills because the game difficulty is not challengeing whatsoever so it makes it useless to grind for levels unless you're a perfectionist) the game fails to keep your interest.
Because of these reasons, the game falls short. This is an essential part of what makes a great game. Without any narrative hook, the game fails to be engaging. The music and the environment REALLY saves this game and it's definitely a highlight that everyone can agree on. However, ultimately, the game dissapoints gamers who is expecting greatness. It has potential for a sequel if its done right. However, if the sequel is going to be like the first one, you can definitely count me out in purchasing a copy.