Why do several Nintendo games have arguable genres?

[Mr Khan]

With Metroid, non-prime, it was definitely an Adventure game. In the case of Prime, i would call it an FPS, but that doesn't preclude the adventure portions of the game. FPS is a very broad genre defined by it's name. It's in first person and you shoot things, thus it's an FPS, but that doesn't mean all FPSes are created equal. CounterStrike is not Time Crisis is not Metroid Prime is not TimeSplitters is not Halo, etc.