Regarding this business of whether Prime 3 is a real Metroid game (and likewise for Hunters)...
One thing I was trying to establish in the first section of my review is that Corruption is the least like a Metroid game yet, at least in some ways, and yet that is actually a good thing because Retro has created something so amazing and original and yet still knows how to pay homage to the original games. Hunters is also not much of a Metroid game, but that's a bad thing in its case because what it is instead pretty much blows. (I'm only referring to the single-player part.)
So yeah, I was actually trying to compliment Corruption with that remark, but I can definitely see how it could be misconstrued. It's a complex argument to make about a very complex game and series, and I did my best to keep the thesis brief so I wouldn't bore people to tears with a lot of academic philosophizing right up front.