Hunters succeeds as an impressive FPS, but not so much as a Metroid game.
Once you get over the steep learning curve, you'll realize how totally awesome the controls are. Although it's not quite as perfect as the revolutionary controls for Metroid Prime 3, it's certainly a step up from the somewhat clunky controls from the first two Primes. It's also really impressive that the DS can replicate the experience had on it's console counterparts so well. However, the DS's limitations do become readily apparent. Even more than Metroid Fusion or Metroid Prime 3, Hunters is a really linear game by Metroid standards--easily the most linear in the series. That's not so say that Hunters is a bad game. On the contrary--Metroid Prime Hunters is a really fun game in its own right, and actually takes the series forward in a few ways. Traveling to different planets and getting some control over your ship is a cool addition, and there are some really neat new weapon upgrades and items to get.
It's not all great, though. Like I said earlier, the game is really linear. Now, it's possible to get lost, but that's only because the halls in certain areas sometimes look way too similar, and the map on the bottom screen is worthless (there is a better map on the pause screen, though). Given the smallness of the DS, you're bound to get some hand-cramps in some particularly intense fights--you know, the most inconvenient possible time for you're hand to stop working. Also, the whole game structure is a bit repetitive.
Despite all it's faults, Metroid Prime Hunters is still a very solid FPS title for the DS. It gets a lot of things absolutely right (the awesome morph ball puzzles need a serious shout out), but sometimes it just doesn't feel like a Metroid game. However, whether you're a Metroid fan our not, Hunters is worthy of a purchase, even if it's not as mind-blowing as its console counterparts.