When word first got out that Metroid's first foray into the third dimension would be from a first-person perspective, reaction was generally negative. Understandably so, since Metroid is widely considered to be one of the best game franchises of all time, and it got there operating in the basic, side-scrolling perspective. People thought the third-person perspective would be the best translation, as was the case with Mario and Zelda.
But when Metroid Prime hit shelves, no one was saying a bad thing about it. The transition was flawless, the gameplay both true to old games as well as innovative, and the graphics simply stunning. Now all the once-embattled development firm Retro Studios has to do is not screw it up. And by the looks of it, they won't.
The back story behind Metroid Prime 2: Echoes, is that a squadron of Galactic Federation troopers were assaulted while on a distant planet, Aether, which is split into light and dark worlds. You are contracted by the Galactic Federation to go in and get them out. The wording used by the game is "render assistance," which leads us to believe some cooperative play may be involved in Echoes, and even if it is only with computer run Galactic Federation troopers, it would be an interesting and fun innovation.
The first thing to notice about Metroid Prime 2: Echoes is that graphics are fine tuned. They're not on an entirely new level, but they're definitely better. Things look sharper, walls are less jagged, and even upon the closest inspection, pixelation is dramatically reduced. Given the awe-inspiring quality of Prime's graphics, Echoes looks to blow people away.
Though not much is offered on the demo disc in terms of Samus's weapons and suits, it is clear that we can expect a totally new arsenal, including Light and Dark Beams. The interesting thing to note about these two particular weapons is that they operate on limited ammunition, like missiles. Recharges seem to be more common and easier to come by than missile ammunition, but it nonetheless adds an element to the game not found in Prime.
Light and Dark is definitely the recurring theme in Echoes; the game is, in grand tradition with Nintendo's ideology, divided into parallel worlds. There are Light and Dark beams, and by the look of things, there will be Light and Dark visors and suits as well, and perhaps more. It's not clear whether old favorites like the X-Ray and Thermal visors or the Phazon Suit will be back, but we can expect Retro Studios won't let us down in that regard.
Continuing in that theme, and picking up in large part where Metroid Fusion left off, there is a Dark Samus to battle. We see a glimpse of this tenebrous doppelganger in the demo disc, and there will almost certainly be many confrontations if not battles with this foe throughout the course of the game.
One much loved feature of Samus's arsenal lacking from Metroid Prime was the Screw Attack. This move provided not only an unstoppable weapon, but also a very handy form of transportation. Beyond a doubt the Screw Attack will be present in Echoes. It looks to use the same 3rd Person interface as the Morph Ball, and there is no reason to believe that it won't be as simple to use and easy to change as the Morph Ball in Prime.
Another nifty addition to Samus's range of weapons and abilities seems to be multiple-targeting. In the preview, we can see Samus targeting numerous objects and firing away at all of them at once. The Scan Visor has gotten an update also, as the visor highlights all scannable objects, and also the Scan and Combat visors' interfaces have received some aesthetic work as well.
One notable feature of the Dark Aether half of this game is that, at least in the demo disc, the atmosphere of the dark world is harmful to Samus's suit. We can safely presume she will at some point acquire a suit capable of handling this atmosphere, but in the meantime she must navigate using "Luminoth Crystals" that extend a safe zone for Samus to stay in. She must charge these with her Light Beam, and can potentially destroy them with her Dark Beam. This will undoubtedly offer another interesting and new bit of gameplay for Echoes.