In the meantime, I'm going to break this down into parts in standard review fashion.
Gameplay/Control (because they're more important then graphics so nyah):
Translating an established franchise to a new dimension is a daunting task these days and Team Ninja did give it the good old college try. Eschewing the first person viewpoint of the Prime series, those at Project M tried to go for a rough semblance of how this franchise would have been if 3-D technology had existed from the dawn of videogames. That is to say, by semblance, I mean a clunky pastiche of two different perspectives that are necessary to awkwardly switch through to proceed in the game. The majority of your time you're going to be running around in a sort of 2.5-D as Samus makes her way through 3-D environments with somewhat manageable 2-D styles of control by way of the D-pad on the Wiimote when you're holding it sideways. The rest of your time in the game is going to be swinging the Wiimote around to point directly at the screen so you can fire missiles, hoping that the need for doing so isn't going to come up when a boss is about to swallow you whole. Needless to say, switching the orientation of the controller isn't the smoothest of ways to transition control and it often ends up with you wasting a missile before an gigantic claw smashes you to the ground. The major irritation that comes from this is that Other M is not a particularly challenging game; most of the difficulty you're going to experience from it is related to this strange control scheme. In tandem with the intentional choice of there being no energy or missile pickups the game seems like an odd fit with it's predecessors.
On paper a lot of this game's great, foremost of those qualities being the visuals. It looks better then pretty much anything else that's been released on the Wii and maintains multiple effects with virtually no slowdown. It's an undeniably gorgeous looking game but you'd expect nothing less from Team Ninja as graphics are very much their specialty. Sadly they're very much smoke and mirrors meant to distract you from the numerous flaws that are present in the game. More tragic then that is that it seems to have worked with most people. All the characters look right, excusing the awkward appearances of some of the minor soldiers without their helmets on. There's not much else to say about the graphics: in a word, excellent.
Wow, this is the big one. This game is without a doubt, the single greatest argument that Nintendo should stick to their own style and not make attempts at emulating that of others. This is the first major franchise Nintendo game that has Voice-over and Cinematics which is a grand change for the Big N. Sadly, it falls flat on it's face. The voice actress for Samus is pretty wooden and fails to make you care about anything she's going through, which is further emphasized by the somewhat ridiculous nature of the story. There wasn't a single surprise in the games plot other then the number of threads they chose not to resolve. We never find out exactly what 'Other M' stands for which is unusual in a game that hammers you over the head with 'subtle' touches like Samus emotionally collapsing when Ridley shows up. We've got an idea, but in light of everything else in the game being about as discreet as a building collapsing on top of you, it seems strangely absent. There's another mystery involving an assassin on board the ship that we never get any resolution on, outside of an updated character profile in the exploration that follows defeating the final boss.
Whereas prior games haven't made a gigantic deal out of Samus being a woman, that's front and center here to the point of absurdity. Team Ninja has a certain reputation in relation to gender equality and considering that one of the FMV's visually compares Samus' emotional state to that of a terrified, crying child you can probably guess what it is. It's a good thing the burly Galactic Federation Soldiers are around to show Samus how to keep those bothersome emotions in check, lest her being a woman prevent her from saving the universe and all. Everything in the game seems to be a metaphor for something, a Freudian field day for those who don't think women can function without strong male figures in their life. When it doesn't touch on that, it focuses on some awkward motherhood element perhaps best embodied by the fact that the game takes place on a "bottle ship" that's emitting a "baby's cry distress signal". The game's strange sexism is likely best embodied by the fact that Samus starts the game with 95% of her powerups; the Grapple Beam, the Shinespark, the Super Missiles they're all here. Rather then using the franchise standard of severe suit damage taking these spectacular abilities away, Samus decides not to use them so she can show her former commanding officer she's capable of following orders.
I'll let that sink in for a second.
Yes, even though she's no longer under his command in an official capacity, Samus decides that she shouldn't use her equipment until she's given permission. This is especially ridiculous when you enter an environment where you're constantly taking damage UNTIL you're told it's OK to activate the Varia Suit. Strange, considering that the only benefits of the Varia Suit are non-offensive. It's like walking around without shoes until someone tells you it's fine now, after having already crossed a field of broken glass, you can handle the big responsibility of footwear. Additionally, the huge proliferation of cinematics makes the game seem longer then it really is; with them removed, actual playtime is somewhere around 8 hours.
I'd hesitate to recommend this game to anyone but the most dedicated Metroid fans and even then it'd be with a grain of salt, as it's pretty detrimental to the character of Samus. Most people seem to be agreeing with the fact that the attempt at a cinematic style is an overall failure but I guess it's one they're willing to accept if it means they can get their Zelda by way of Lord of the Rings they've been thirsting for ever since voice over became the industry standard. People want it BADLY and they've been very vocal about Link talking ever since they saw the cartoony style of Windwaker.
I'd like to think that if Nintendo's going to try and get more ambitious with their storytelling they should experiment with it in house as opposed to going through a third party. It's easy to see why they tried this with Metroid first though; at this point it's far too awkward a fit for Mario and people would DESTROY a Zelda game if it exhibited a similar failure to engage. That's a sad place for Metroid to be in: well-known, but not popular enough to cause a total fan meltdown if it has any failed experimentation. It's not a complete disaster but that's sort of rationalizing Zach Snyder directing Superman with the fact that it's not Paul W.S. Anderson.