There was a mere two year gap between the release of Metroid Prime and Metroid Prime 2: Echoes, one fourth the time it took Nintendo to make the leap from Super Metroid to the aforementioned. Although Nintendo spent only three years on Metroid Prime and weren't cooking the game for the full eight years they were neglecting the franchise, the difference in numbers led a small number of less observant Metroid fans to speculate as to whether Retro could repeat the same success in such a short time. Metroid Prime 2 was received well critically, but was lost amongst the Q4 '04 bin of Half-Life 2, Metal Gear Solid 3: Snake Eater, Grand Theft Auto: San Andreas, and of course Halo 2. As if in a half-hearted attempt to parry the latter, Retro added a split-screen multiplayer component which was passable, but not remarkable. Fortunately, the single-player game was not compromised by the addition of the multiplayer modes, and was very well-received.
The game had two significant (and one insignificant) assets: it was a visual wonder and is arguably the best-looking game on the Nintendo GameCube ever, and features some of the most inventive and challenging boss fights in the Metroid series. Metroid Prime 2 also features one of the most inventive menu systems to this day: a sort of orbital format where things are rotated to the foreground to be selected.
In the style of Halo 2's I Love Bees alternate reality game, Metroid Prime 2 also had an online viral marketing campaign. The campaign consisted of two websites: Orbis Labs and Channel 51. Orbis Labs was apparently a weapons development company that was, at the time, working on a piece of machinery known as the Battle Sphere, a nod to the Morph Ball featured in the Metroid series. Channel 51 was a blog in the style of a typical conspiracy theory website. Run by a "Samantha Manus," Channel 51 featured distorted Metroid Prime 2 footage as supposed video evidence of alien visitation to Earth, as well as other hints alluding to a few gameplay elements. When Metroid Prime 2 actually came out, "Manus" posted one last blog message bitterly complaining that she had been tricked and that "it was all for a video game", leading some less intelligent fans to wonder whether Channel 51 was a real conspiracy theory website that had been deliberately mislead by Nintendo to advertise their product.
Metroid Prime 2, taking place six months after the events of Metroid Prime, (which itself took place in the years in between the original Metroid and the Game Boy sequel Metroid II: Return of Samus) revolves around the conflict between two races, the Luminoth and the Ing, on the planet Aether. Centuries prior to Samus' arrival, Aether was hit by a meteor of Phazon, duplicating the planet in a Dark realm, thus splitting the planet into two parallel universes. The Dark version of Aether became home to the Ing, a race of malevolent creatures of pure darkness, able to possess both organisms and machines. The Space Pirates, upon recently discovering Aether, had decided to harvest the Phazon in order to make up for their defeat on Tallon IV. Samus Aran is sent to investigate, where she learns that the Luminoth, the original dwellers of the "light" Aether, had all but lost an ongoing battle between them and the Ing. It is Samus's mission to restore peace to Aether by defeating the Ing while simultaneously ridding the planet of Space Pirates and the mysterious Dark Samus, a hostile duplicate of Samus who clearly has some connection to the Phazon corrupting the planet.
Metroid Prime 2 played the same as Metroid Prime, with a few minor improvements. For one, scanning was greatly improved, by removing the scan targets, instead allowing you to scan anywhere on an object/enemy. In addition, objects and items are now colour-coordinated. Important scans are now in red, and less important scans are now in blue. Objects you have already scanned are now in green. These refinements make scanning much easier in comparison, and was there once again in the Nintendo Wii sequel Metroid Prime 3: Corruption.
Another additional is the controversial use of ammo for energy beams; although the standard Power Beam has unlimited energy, as always, the new Dark Beam and Light Beam have a limited supply of ammo. Killing enemies with the Dark Beam nets you light ammo, and vice-versa, in addition to being able to replenish your supplies with crates and ammo stations. Using the Light Beam on "dark" enemies or the Ing kills them faster than your normal Power Beam, and the Dark Beam kills regular enemies faster. Finally, the "Annihilator Beam", which is extra-effective on all enemy types, uses both Dark and Light ammo to fire. Charging shots for all three weapons creates more powerful attacks, but drains more ammo than normal. Because some doors must be opened with different beams, just as in previous Metroid titles, even if a beam has zero ammo left, the player can "charge up" the empty weapon to fire a single regular-powered shot.
The final aspect of Metroid Prime 2 that differs from Metroid Prime is the Nintendo tradition of light and dark worlds. While normal Aether will not harm you in any way, the corrosive atmosphere of Dark Aether will constantly drain your health until you die, although pools of light scattered about by the Luminoth during their failed invasions of Dark Aether will protect and even heal Samus; indeed, because these pools of light will actually heal her health fully instead of just replenishing damage suffered by the corrosive atmosphere, Dark Aether is actually safer for Samus since she can always retreat to the safety of a light pool and wait to become 100% healed. Eventually, Samus locates the Dark Suit upgrade, which greatly increases her resistance to Dark Aether's atmosphere, slowing down the rate at which it burns away her health, and later on the Light Suit, which renders her completely impervious to the dark atmosphere, though pools of light will still heal her.
In Metroid Prime 2: Echoes, you earn a wide variety of weapons and power-ups through the game to aid you on your adventure. Although you start out with some of them, they are taken away early on.
Your default weapon, which allows you to fire the fastest. You can also Hold the fire button to charge it, otherwise known as your Charge Beam.
The light beam can go through multiple enemies, and it has the possibility to set enemies on fire. This uses light energy ammo. Charging it allows you to fire a Lightblast attack, which costs 5 Light ammo to use.
The dark beam fires shadow energy, which has the possibility to slow down enemies and objects. This uses dark energy ammo. Charging it allows you to fire an Entangler attack, which costs 5 Dark ammo to use.
This beam combines the power of the Light and Dark beams, and uses both light and dark energy to use. Charging it allows you to fire a Disruptor attack, which costs 5 of each type of energy ammo to use.
The Sunburst is the Charge Combo for the Light Beam, a slow moving, widespread attack which will set enemies on fire. Using it requires 5 missiles as well as 30 Light ammo.
The Darkburst is the Charge Combo for the Dark Beam, which opens up a portal to a dark dimension, pulling enemies into it. Using it requires 5 missiles as well as 30 Dark ammo.
The Sonic Boom is the Annihilator Charge Combo. Using it costs 5 missiles, 30 light ammo and 30 dark ammo.
This allows you to fire Missiles, and you can either fire them with or without a lock-on. They can also destroy objects made of Brinstone.
Seeker Missile Launcher
This weapon upgrade allows you to fire missiles at multiple targets at the same time by allowing you to charge your missiles. Stupidly, you cannot engage the Seeker Missiles without wasting a single missile first in order to engage the system. You can also lock onto the same enemy multiple times.
By charging your Power Beam then using a Missile allows you to fire a Super Missile. Using the Super Missile costs 5 missiles.
Morph Ball Bomb
This is your default weapon while using the Morph Ball. It can also be used to break cracked walls as well as perform a power ball jump. It can also break items made of Talloric alloy.
This is the strongest Morph Ball weapon. It can destroy a lot of materials, including Denzium, and each expansion you get for it will increase its capacity by 1.
Suit Expansions are nothing new to the Metroid franchise, but in this game they brought some more familiar expansions into the 3d realm as well as some new ones.
The Morph Ball allows you to travel through tight corridors and travel faster overall, and is upgradeable.
This upgrade allows you to quickly speed through areas, and you can also charge it up. By charging up your boost ball in some devices, you can solve some puzzles as well as get past some obstacles. You can also damage some enemies by boosting into them.
This allows you to move across magnetic rails. By combining this with the Boost Ball you can propel to other Magnetic rails, a feature not present in the original Metroid Prime.
Space Jump Boots
These allow you to jump higher as well as perform a double jump.
This allows you to move through water without limitations, so in essence, it's the Gravity Suit, but not in suit form. By combining it with the Space Jump Boots in water, by holding B you can slowly rise and move through water.
This allows you to swing back and forth using grapple points found in the game. You can also change your direction while swinging.
This allows you to turn into a moving weapon while jumping. You have a limited amount of jumps, but you can also slightly steer where you are going as well. You can also perform a wall jump while facing a special wall surface and bouncing off it in midair.
This is your default suit, and while on Dark Aether, your energy is drained rapidly by its atmosphere.
This suit decreases the amount of energy you lose while on Dark Aether through its atmosphere.
This suit negates all damage you take from Dark Aether's atmosphere and you won't be impeded by its water. This suit also allows you transfer quickly through Aether's regions using teleportation.
This is your default visor, which allows you to view your ammo meter, the amount of missiles you have, as well as your health meter.
This visor is used to collect data on anything, enemies included. Some devices will also activate when you scan them. All scans will be recorded in your logbook, and keep in mind that there are different colors of scans for the most important things.
This visor allows you to see invisible objects and enemies as well as highlight enemies as a targeting aid.
This visor uses sound to detect invisible enemies and objects, but is mostly used to interact with sonic-based security systems.
On August 24th, 2009, Metroid Prime 2: Echoes was re-released as part of the Metroid Prime Trilogy collection on the Nintendo Wii. The new version supports 16:9 widescreen and Wiimote pointer controls similar to those used in Metroid Prime 3: Corruption.