The gameplay is actually OK, but there are some things that made me question what the developers were thinking.
-Mid-exploration and with some attacks, everything is fine. You run, jump, shoot, interact, everything's slick and great. This is actually done really really well, even though you're running around in a 3D environment, it doesn't feel weird or anything.
-But then, for some reason they made it so that you ONLY use the Wii remote to move (no analog control, no extra buttons). Okay...
-and they made it so that you have to enter First-Person Mode by pointing the Wii remote at the screen in order to shoot missiles, and expose enemy weakpoints. Essentially, that 'mode' feels like a different game, a 'crappy Metroid Prime', essentially.
-in this mode, since there aren't many buttons (Wii Remote Only), you have to do questionable things to dodge attacks. I forget what the maneuver was (not sure if it was pressing the bottom B button, or shaking the remote) that you had to do to dodge.
-you also had an unlimited supply of missiles. They handwaved it saying they were 'energy missiles' so Samus's suit woud auto-recharge the gauge with time, but it feels weird to not collect missile expansions in the same fashion as in other games.
-it's got a worse problem than Metroid Fusion when it comes to the whole "Wait Until Authorized" to use certain abilities Samus has already kept from previous games. Some of these make sense (don't detonate a large PowerBomb in the ship as this is an area with scientists and navigation crew, etc. etc. you're endangering lives blah blah blah)... while others make no sense whatsoever (why wouldn't Samus have the Varia suit or Gravity Suit turned on by default? What harm is it doing? Is it ripping a hole in the ship using gravity-defying powers? They didn't even bother handwaving this one).
If they didn't do the first-person mode, it probably would have ameliorated the public's reception to the game.