Making a followup to a resounding success is no easy task. Retro were challenged with such a task, and they delivered!
When you begin playing Metroid Prime: Echoes you're once again stripped of your weapons and armor, and so you once again set out to expand your armament while uncovering the secrets of the Dark Ing. The light and dark side of Aether reside alongside each other, and so you have to do dimensional jumps between these worlds in order to uncover the secrets of the Ing invasion. Things that aren't available on the light side might be available on the dark side, and vice versa, and certain things need to be activated on each side to make things in the corresponding side available. The dark side is invading the light side, and only Samus can prevent it from consuming the light side completely!
The story in Echoes is engaging and fascinating, although the ending doesn't reveal as much as you'd like about the plot, but the story in Echoes is a well written and well executed one. The graphics is stunning, the differences from Metroid Prime are small and subtle, but why change a winning formula? The graphics in combination with very impressive sound makes the atmosphere in Echoes an impressive one. The attention to detail is impressive, and the different environments in Echoes really shows the capabilities of the graphics engine introduced with Metroid Prime.
Is it all green acres then? No, Echoes does have flaws, albeit minor in comparison to other titles. The constant jumping between the light and dark world can become quite cumbersome towards the end. Especially when it comes to searching for the keys to the final temple. Sorry, that may have been a spoiler, but you had the same thing in the first game so it isn't really that much of a jaw-dropper. In order to find these keys you're forced to do a hefty amount of inter-dimensional jumping, something that becomes a tad bit repetitive. These keys are themselves a flaw compared to the first title. In Metroid Prime the search for artifacts are more fused with the storyline whereas the search for keys in Echoes feels more like it was tossed in to keep the title's checklist towards the first incarnation intact. Although the first Metroid Prime is a better game when it comes to the overall feeling, Echoes is an amazing followup.
Despite these flaws, the only reasons for me not giving the title a few notches higher of a grade is that the first part of the Prime series had a better overall Metroid-feeling to it. This is a truly amazing adventure and an impressive production. If you're a fan of the first title in the Prime-series, a Metroid fan or simply a fan of great games, this is a title which every self respecting GameCube owner should have! Well done Retro!