There are a few issues I have with this game that would preclude my giving it a 10:

1. The camera: It's pretty good most of the time, but when it's not, it really irritated me. You can't even control it as well as SM64's. And why can't I pan it around or even go first-person all the time? It also likes to shove a land mass between itself and Mario so I can't see what I'm doing or where I'm going. When it switches position on places where you go from one orientation to the opposite (like in Dusty Dune's donut areas where you go on the opposite side), I sometimes find myself going in and out, in and out, just because of control and camera issues. The camera doesn't function well for swimming or red-star-flying, either. I went for "completion" last night (i.e. I got 120 stars) and I came to hate the camera. But like I said, it works fine MOST of the time.

2. Acrobatics: Thankfully, wall jumping is easier to perform. However, I find it harder to do triple jumps and the backflip is less precise in a way, as someone else already mentioned. In SM64 a backflip would let you grab onto a ledge if you reached the ledge's height with it. Not so here. Here you have to go a bit higher, and many times when I do a backflip and I'm trying to get up to some place, I don't know if I made it until I see Mario sliding down the wall, ready to do a wall jump... which, needless to say, I was not wanting to do.

3. Control: This may just be my own personal problem, but I find it difficult to control Mario when he's not oriented normally, and especially when I switch orientations. As I already stated, the camera gives me problems here, too, which just compounds my own control problems.

Those are really the only complaints I can come up with. I don't score my games, but if I did, I'd give this a 9.5, easily. But these problems make it impossible for me to give it a 10.