The Metroid Prime series uses a first-person shooter interface, but the gameplay is more about trying to get somewhere, not being able to get past an obstacle, going somewhere else, getting sidetracked, getting additional ammo or a life meter extension that helps you beat the enemy you sidetracked by, which then leads you to a new item that will let you get past that first obstacle. And so on, and so forth.
The old Metroid games were basically Zelda as a side-scrolling action platformer; the Prime games just use an FPS framework to move it into 3D, but you don’t have all that many weapons (an infinite ammo energy gun that uses a kind of elemental-weakness mechanic, with ammo-based secondary weapons when you need extra firepower), and the game uses an auto lock-on feature where you hold one button down and it automatically tracks the target so you can just maneuver and keep firing. In other words, you really don’t need to have any skill with FPS gameplay to get by.
The first-person can make the platforming elements tricky, but the game is pretty well designed in this respect, so if you have any experience with platformers you’ll do fine as long as you go by your gut and keep moving. Over-thinking it tends to cause me more problems. Edited to say: I kind of agree with pedescribe, but kind of don’t. I haven’t played more than 1/4 of Prime 2 and none of Prime 3, but I beat Prime and there was a fair bit of platforming, but it’s really not that hard. the Prime games are easier in that regard than the 3D Mario games or Spyro, for example. If you liked the new Prince of Persia games you’ll do fine.
The theme of Metroid games is exploration and isolation. It’s dark, foreboding, and lonely, but you get a neat storyline with some pretty amazing vistas as you explore, and if you scan all the extra details for the fluff text there’s a lot of interesting backstory and world-building. Plus, when you’ve got a bunch of the power-ups, you get to roll around feeling like a total bad-ass.
I’ve always liked the Zelda and Metroid series for the same reasons: the exploration, puzzle-solving, item upgrades, and elaborate boss fights. If these are what you like about Zelda I’d say give Metroid Prime a shot, because you’ll probably like it.