I recently finished playing Metroid Prime: Echoes for Gamecube.  I got it back in November when it came out but at the time I put it in, played for about 20 minutes, decided it was mostly the same as Metroid Prime and put it away for awhile while I worked on Tanjunka.  Recently though I decided I had some time so I went back to it.  Here are my impressions

Basically it's almost the exact same game as the original Metroid Prime.  There are only a few noticable differences.

1) There is the concept of the light / dark world.  While that's not a new concept it is new for Metroid.  One thing that sets it apart, at least for me, when you are in the dark world it's almost as though the atmosphere is made from acid and it's eating your suit.  Your hit points fall.  But, inside the dark side are bubbles of light.  The effect is quite nice.  While you are inside a bubble you're relatively safe and your energy slowly climbs back up.  It's a fairly new feeling to be running from bubble to bubble as fast as you can.  You jump outside a bubble and it's PANIC until you make it to the next bubble.  Very cool.

2) A mostly minor change, they changed the 3 of the 4 visors and 3 of the 4 weapons.  It's not that it really matters.  The 3 new weapons in Metroid Prime Echoes are just basically replacements for the 3 other weapons in Metroid Prime.  Each opens a specific type of door, each effects a different type of enemy but really it's nothing new.  The visors are a little different, I especially liked the Echo Visor which has a very cool effect.  At least it's different.  The other visors are really just subsitutes for the ones in Metroid Prime although their effects are nice.

3) They added the spin jump back in from the 2D series.  It nice to see it although it doesn't really add much to the game.

4) It's even more beautiful than the first one and that's saying something.  Many of the areas are just breath taking.  The last area, a cyber, computer like area, was probably my favorite but even at the beginning of the game, the first room you walk in is full of larva and the second or 3rd is full of spider webs and bug eggs with moving stuff inside. It's really gross and very well done.  I don't think I've ever been as creeped out just by the graphics alone as in Metroid Prime Echoes.

Some of the enemies as well are amazing.  Slime based enemies that slide across the walls.  A floating spider like enemy that rezes in and out of existance is amazing and scary.  A Tron line "Bit" enemy that ruins your suit and makes everything look like a webcam on a modem.

On the downside, the more experienced or older I get the less I like dealing with stuff in a game that is out of place, that breaks the suspension of disbelief.  Most games are guilty of this.  Some, like Mario and Sonic are clearly 100% games and so you can put anything in their make−believe worlds of stripes and colors.  Others though like Metroid, GTA3, Halo etc are set in a semi real−world like setting and so when things don't make any sense they stick out. Metroid is one such setting.  In the original 2d, being more abstract, it worked well.  But in 3d, as it gets more and more real it starts to become apparent just how silly it is that Samus is visiting a planet she's never been to and yet all the machines and levels are specifically designed for a power ball.  What, did the original inhabitants carry around power balls just to charge their machinery or open doors?  I know it's the convention for Metroid but still...

I'd have to say the beauty is probably the #1 thing that kept me playing.  I mean, as a game it's as good as the first and it's arguably not as hard, I beat the last boss second try.  At the same time it's not very new so if you played the first and you want more then check it out but if you didn't like the first one you are not likely to like this one either.

Still, looking at it with a techincal eye, they apparently have a system where they can use 2 layers of textures anywhere and everywhere and at least one of those layers can be scrolling.  They use that simple ability to make the entire world come alive with moving things, glowing spots in walls, circuit systems, oozing slime monsters,etc.  It's a simple effect that was probably available in some other engines but until Retro's artists got to use it no one had really understood all the creative things you could do with such a simple system.  The beauty of the levels alone was worth it for me.