There are some disappointing aspects to the campaign, though. For one thing, the level design feels more linear and uninspired than in any other Metroid game. Sure there are simple puzzles to solve, maybe a couple branching pathways here and there, and some morphball mazes, but the unified, organic level design that typifies the Metroid franchise is missing. Instead, Hunters offers a cookie-cutter feel to its planets, with sometimes repetitive room architecture. You'll make your way down a mostly obvious path, picking up energy tank and missile upgrades or maybe a new gun. You'll then take out a bounty hunter and a boss (many of which are recycled), grab your octolith, and leave. After picking up an octolith, you'll have to quickly evacuate to your ship as a countdown timer ticks down--this makes no logical sense, though, as nothing happens when you reach your ship. There's no dramatic escape from an exploding planet (you do have to come back later, after all) and nothing that suggests what the urgency to leave was in the first place.
The multiplayer aspect to Metroid Prime: Hunters holds, perhaps surprisingly for a Metroid game, more appeal than its single-player game. You can play with up to four players locally through game sharing or multicard and online for up to four players through Nintendo's Wi-Fi service. Single-card game sharing limits you to playing standard battle (deathmatch) mode, and all players have to play as Samus. However, multicard battles and online play let you use any of the bounty hunters you've defeated in the single-player campaign. Each hunter has a unique alt form (such as Samus' morphball) and special weapon. Weavel, for example, can split himself into two, with his bottom half being an automated turret, while his top half can run around and melee or find more power-ups. Each character has different strengths that can be exploited depending on the arena, though not all can be used with each game mode.
For multicard play, a number of different other game types are available, including one- and two-flag variants of capture the flag (or the octolith, in this case), last man standing, king of the hill, and "prime hunter." The latter is a variation of assassin where one player has the prime hunter designation and must hold it for as much time as possible while others attempt to kill that player and take the title. Team play versions are available for the appropriate game types. The game host has the ability to set options for point limits, time limits, and even restrict the use of radar and other options. You can insert bots of varying skill levels to play against to fill out the rest of the field, so you don't necessarily need three friends with the game to enjoy these multiplayer modes. The bots offer a respectable challenge at the higher difficulty levels and are worthwhile to play against if you can't scrounge up some buddies. To help you on that front, a rivals radar is included, which is similar to Nintendogs' bark mode--set this option on, put your DS on sleep, and any other Hunters owners you pass by who have their rivals radar on will be added to your rivals list. Presumably this allows you to build up a nice list of opponents for online play, but its utility is questionable for anyone outside a large concentration of other DS owners, like in a school perhaps.
Online play for four players is also available. Searching for a game is as simple as logging in, and Nintendo's Wi-Fi service will automatically match you up with three other players. Once you're logged in, each player has a few seconds to select their preferred hunter before the game automatically loads up a voting screen for players to vote on the map to play. The online action was smooth and lag free in our experience, and you're likely to find stiff challenges online against other human opponents. The game ranks you based on how many kills you get and matches you play and keeps track of other stats, such as your favorite weapon, how many kills you get in bipedal or alt mode, and others. The strategies are pretty young at this point, but a popular one so far seems to be using a hunter with a melee-attacking alt form to charge in and spam close-range attacks.
Online play is overall quite fun, but it has its quirks. For one thing, the only mode you can just play online right from the get-go is battle mode. The only way to access the other online modes is by playing against those on your friends and rivals list. So while it's all well and good that you do have access to all the multiplayer modes online, the fact that you have to input lengthy friend codes in order to access all of the game modes is annoying. Once you do that, you can see who's online and host a game or join an existing game that's open to you. You can even send voice messages to each other while in the lobby of a friend's (but not a rival's) game, or send text-based messages that you can type in using a keyboard that appears on the touchscreen. Both communication options work pretty well, but once the game starts, you can't message each other anymore, so the trash talking ends.
Despite those caveats, Metroid Prime: Hunters is an excellent multiplayer game and easy to recommend to anyone who enjoys FPS action. The single-player is also well worth a play through, despite its limitations, if only to take in the story and unlock all the hunters for multiplayer action.
Editor's note 03/23/06: Our review originally overlooked specific aspects of the friends/rivals system, which required a reevaluation of these parts of the game and a revision to the text. GameSpot regrets the errors.