Metroid Prime 2 Echoes is the second Metroid game to hit a console in as many years. This is a quickie sequel by the standards of the series -- leave Echoes out of the equation, and Nintendo released three console Metroids over 16 years. The speedy turnaround shows, too, at least (once again) by the standards of the series.

There's an argument to be made that this isn't quite as good a game as Metroid Prime. Certainly it's not as shockingly new as the original Metroid, Super Metroid eight years later, or the series' first excursion in first-person 3D. It's weaker in a few areas and leaves some of its predecessor's flaws uncorrected. But it also shares many of its unique strengths, which are more than enough to justify seeing it through to the end.

Retro Studios has a knack for a few things that nobody else in the business seems quite as good at. First-person platforming is one of them. You may fight the controls in Metroid Prime some of the time. In fact, leave the "may" out -- you will go to war with them in multiple boss battles. But hopping around the game world in every direction is practically effortless, no matter how many narrow ledges and moving surfaces get involved. It's still hard to say how they do it. Like the Colonel's special recipe, the formula for an FPS jumping puzzle that doesn't inspire venomous rage is locked in a vault somewhere, never to be shared.

There have been some complaints about the difficulty level in Echoes, but it's not unusually tough from my perspective. Only one boss, the Spider Guardian, seems clearly out of line -- it's nothing but platforming with the Morph Ball Bomb, which is about as much fun as having your teeth pulled by a blind man, and it's one of a few instances of poor save point placement. It wouldn't be coddling the player to simply offer an automatic save after a boss battle. Other major battles feature lesser aggravations at worst, the usual Metroid Prime aggravations involving the bad guys using the limitations of the lock-on controls against you, and some are a genuinely good time. Spider Ball platforming is as much fun as bomb platforming is not, making the Power Bomb Guardian a kick.

Art direction is another one of Retro's strengths. The art galleries in Prime 2 (unlocked, as per usual, by scanning bits of the environment and filling out a logbook of zoology and history) are beautiful, and the creations on display are beautifully realized in the game. Echoes, like Metroid Prime before it, creates worlds that feel seamless and natural, even if they just look like interconnecting corridors on the 3D map. Kenji Yamamoto's score has only one section where it sounds less than solid, and the sound design (distinct from the music) has some very cool effects, making this a game best played with headphones or a good surround setup. The scenery's so nice that it's a shame there isn't more of it. The original Prime had more distinct areas and more level themes than Echoes by a fair margin, although Echoes recovers some of that margin by featuring dark mirror versions of each main region.

Samus herself might be the one aspect of the game that doesn't look as cool or cooler than the original. The Phazon Suit from two years back is still much, much sharper than any of the suit designs in Echoes. The game's bestiary makes up for some repeating designs with top-notch original creations (from the hulking Ing shadow-beasts to clever concepts like the digital Rezbit baddies), but it's still a shame Samus hasn't got style to match the opposition.

Her new loadout of equipment might also be a bit of a disappointment. The beam selection in Echoes is probably better than Prime's -- with just the Light and Dark beams doing most of the heavy lifting, it's easier than dealing with three secondary beams for a long stretch -- but the rest of the extra gear is a mixed bag. Some of the niftiest upgrades get short shrift because they have overly specialized uses, or because there isn't a lot of game left to explore after you grab them. The light and dark charge combos aren't all that vital or indeed even helpful in combat most of the time. The Echo Visor is a fascinating piece of work, turning the view into a flickery shadow-picture created by sound bouncing around the room, but it's not used in gameplay as much more than a glorified key. It has a secondary function, occasionally revealing hidden energy tanks and missile expansions, but by the time you pick it up the few remaining upgrades are scattered far away from each other. Which brings up another point.

It's a convention of Metroid games that Samus Aran retraces her steps a lot, tripping back and forth to access new bits of familiar areas with additional weapons and equipment. This convention got started in 1986, though, back in a different age of game design, when it wasn't possible to stuff as much original content into a game. Modern RPGs don't make you grind away through hundreds of repetitive battles, in the style of the original Dragon Warrior, but Metroid still makes you hike around like a Boy Scout on speed. There may be a little too much reverence for antiquity going on here.

The real fun in Echoes is exploring completely new places. It may sometimes be satifying to snag a little something in a hidden cranny of an old area, but the effort required usually exceeds the reward. Retro even recycled one of the most aggravating puzzle concepts from the original Prime in the sequel, the artifact quest that drags Samus all the way back around the world again. This time there are only nine widgets to find instead of a dozen, but that's still not a heck of an improvement. The puzzles involved in acquiring the keys are often very smart -- in general, Prime 2's puzzles are a cut above the current standard in videogame brain-teasing -- but getting there isn't half the fun.

While it might not have been a bad idea in concept, the multiplayer game in Echoes isn't anywhere near half the fun. It's a noble attempt to translate the single-player control scheme to a head-to-head game, but that attempt fails in a mess of cheap deaths and constant struggles to wrench the view in the right direction. With only six maps and two simple game modes offered, it's not going to tear anyone away from most of the other four-player experiences on GameCube.

Even if the multiplayer game has proven a misstep, though, Echoes gives the impression that there's a lot of untapped potential in Metroid, both its gameplay and its overarching universe. Retro could take the series in a very different direction if it makes another installment, one that could be at least as interesting. As mentioned in our first impressions earlier this week, it starts with a quite un-Metroid prologue sequence, involving more characters, a different atmosphere, and new bits of fiction that flesh out the game world a little more. It'd be interesting to see Retro do a whole game that way. Samus doesn't have to be playing sci-fi archaeologist every time.

Retro still makes a fine game of sci-fi archaeologist, though, which is probably more than enough for the first game's many devotees. It doesn't have that amazing "they actually did it" feeling that accompanied Metroid Prime's arrival, but that's something that doesn't happen as often as every two years.