I've just played through the first two hours and the space station intro. I can't understand the criticism of this bit that says it doesn't feel like Metroid - this bit is simply mindblowing and sets the scene perfectly for the rest of the adventure. I loved all of the interaction and the cinematics.
Having just completed Bioshock, Metroid 3 actually looks better. Not in the detail, obviously, but in the sheer creativity and variety. The cinematic feel works much better and the adventure has far more depth.
I am suitably impressed so far at how far this game takes the series. It isn't the minor step forward most reviews had me believe, it's a gigantic leap forward in terms of Metroid presentation. I'm staggered places like IGN have poo poo'd the first section, unbelievable.