Prime pretty much just had you focusing on leaving the planet :/
Well, no, I wouldn't say that. The ultimate goal was to leave the planet, but in the process you were trying to recover information on the Chozo, destroy the source of Phazon, and destroy Meta Ridley, too.
I need to replay Prime 2, as I can barely remember it...but from what I remember, 1 > 2 >> 3.
All three are AMAZING games, but 1 did a perfect job of maintaining the isolation factor that Metroid games really should have, had good ol' sequence breaking (at least, before they "fixed" it...), amazing level design and music, and was overall a great game.
My problem with 2 is that trying to maneuver through the Dark World was super annoying before you get the Light Suit (i.e. approximately 20 minutes before the end of the game). The Dark/Light world concept was well-implemented for the most part, but it wasn't entirely creative either.
I think my largest issue, however, is the godforsaken beam ammo. That is the only major problem I have with the game. It forces you to be careful, true...but it also limits you quite a bit. And then the Annihilator Beam takes 1 of BOTH types of ammo? It restricts you a lot.
Prime 3 is the worst in my opinion, though, because it kills the isolation factor for the most part (once you get to Bryyo it gets better, but even then you have a fair amount of contact), Hyper Mode is really broken (you can't totally abuse it, but you can still abuse it quite a bit), they focused way too much on Phazon and the Phazon expansions which were used about twice each, INCLUDING the time you needed them to exit the Leviathans (and excluding Phaaze). It had some of the best boss battles in any of the three games, it had some good plot twists, but...it was inferior in many aspects.
Plus, the freaking ending. Like, we KNOW Samus doesn't die just by the timeline (Metroid 2, Super Metroid, and Fusion are all still to come after the Prime trilogy), so did they really have to pull one of those fake "OH NOEZ WE LOST CONTACT AN HOUR AGO BUT WAIT WHAT'S THIS" endings? I could probably find at LEAST 5 other instances of that in various movies and books, off the top of my head there's
Independence Day. (Good movie, but I hate that kind of ending.)
It's a pretty awesome game overall, but it's the weakest of the trilogy, in my opinion.
Sonic Adventure DX: I don't know why people hate 3D sonic games, I actually like a couple: Sonic Heros, Sonic and the Secret Rings etc. anyway, I did like this game it was pretty fun, I just generally like these sort of adventure games, story wasn't bad, I actually love just randomally running around IMO (<3 speed), the gameplay wasn't that bad either. The other characters were a lot of fun as well, I felt like I could replay it with all the characters. I don't care what anyone says, Big the Cat wasn't THAT bad >: (
EDIT:Oh and Music = <3 Retract that statement >_>
I know there is something important to add to this, but I forgot >_>
It's not really a GameCube exclusive, though...it's a very loose remake of Sonic Adventure. They really only added the ability to unlock Metal Sonic after getting all 140 emblems and the collection of Sonic Game Gear games.