What's the most "mature" Nintendo-developed game?

[Nighteyes_1981]

Darc Requiem said:

Nighteyes_1981 said:
Metroid would have to be it. It could be a horror movie, the metroids themselves are just damn creepy. Nintendo didn't develop the Metroid Prime series, but they worked very close with Retro on it. It has some rather disturbing images as well as human tragedy and casualties.

 Well Nintendo owns 100% of Retro. So anything developed by them is 1st party.

 Ahh so it is.  I had forgotten that.  Well then the Metroid Prime series is definitely it.