HELL, i love EVERYTHING about this game. I'll start.
Graphics: This game is nearly perfect. Graphically (Considering the graphic limitations of the GCN, and knowing the XBOX is far more powerful) this game is the "creme de la creme" in graphics. Excellently compressed textures, high polygon usage for Samus and characters (Except for when Samus morphs/unmorphs, it's plain to see it's not as detailed as the model they use for the cinematics) nice mist effects, the lava looks quite real, the snow and ice looks like it is really there, the walls are not simple textures of rocks, they also add flora, sometimes fauna to give it a realistic look. It's one of the closest-to-reality games i have ever seen, if not the best. The distortion added when Samus shoots her charged Power Beam, Samus' face when she shoots too close to her, the "TV-without-signal" effect when there's interference, the X-ray/thermal visor's effects, the way the Ice freezes enemies and make them look like a big chunk of ice. The way enemies burn when shot with Plasma... all of that give an incredible potential to this game. Myself, I'm not a pursuer of "hot graphics" in games, yet I have to admit most of this game's merits are due to its incredible, top-notch graphics.
Sound: MIDI. MODI and MORE MIDI - It's hard to believe all of this game's soundtrack is made with MIDI. The thing is, it's so well composed, so well put together, it DOES NOT NEED recorded audio to actually sound good. My props to Kenji Yamamoto. This game's audio has NOTHING to do against other game's "recorded audio". The sound effects also add a lot of reality to this game. Specially when played with Dolby. How Samus' arm cannon clanks, her footsteps thru grass, sand, metal, water.... Wonderful...
Gameplay: I don't see why people complain About this game's gameplay. they say it is too lacky for a FPS. Well, that's probably because METROID PRIME IS NOT A FIRST PERSON SHOOTER. It is a FIRST PERSON ADVENTURE. It means that in order to use the morph ball, it changes into 3rd person (Because playing FP inside of the morph ball wouldn't make much sense). As a player of FPS's I can say it's quite different from that genre. FPS's are about completing missions and finding the way out. Metroid Prime is a METROID GAME turned into 3D, and trying to make you feel as if you were Samus. That's all about it. It does take a LOT OF GUTS to compare this game to an usual FPS. It also takes a lack of analytical skills. Briefing, I can say this game has an adequate control system for a similar-to-a-FPS CONSOLE GAME. It responses good,accurately, and like any good HARD game, it takes time to get used to. That is not a bad aspect AT ALL. That's actually a sign that the game is long, and that you have to dedicate some time to get used to it. The entire gameplay is rewarding.
Let me say it one more time - This is NOT a mouse-played computer game. This is NOT a FPS. THIS IS A METROID GAME.
There's nothing I didn't like about this game - It's nearly flawless. Perhaps the load times between the worlds (when going thru a door). But it's not the big deal. I love this game ta death.
The Bottom Line
Putting aside "sequence breaking" (Proving that you don't have something better to do with your life), this is perfection made game.