@drachmalius: I think you made the point I tried to make, but more succinctly here. One can find the aesthetics childish, that's a legitimate opinion and position, I think, but maturity or lack thereof is a whole different issue and a weird criticism to base on just aesthetics.
As you said, figuring out what you don't like and breaking down the construct "just for kids" and working backwards will get one to a more accurate, regardless of subjectivity, description of their own position and understanding of the situation.
Thinking about what I wrote last night, I think a more succinct way to say what I meant to offer as a counter-suggestion to the OP's impression was this: I like my gameplay dressed in stories, preferably with some mystery or otherwordliness or emotional undertones. When I was a kid - therefore, technically, more immature than I am now - I was drawn to, undoubtedly, immature games despite their mature imagery (e.g. Resident Evil) because of those elements. This is still true for me, and this is why I keep bouncing off Nintendo games despite a lot of them being really good when it comes to gameplay. A present-day example perfectly encapsulating this difference would be if I compared BotW to HZD. I played the latter first, loved it. Playing BotW, one of my (and my partner's who was watching) reactions to the early plot-scenes was "huh this looks like HZD for kids!" (which, btw, was entirely in good-faith, without any undertone of machismo - that was an interesting take - or accusation of immaturity), because it appeared as a simplified variation of the HZD story in a way. This comparison would aptly apply to exploration and collectables, too: one game offering socioenvironmental and emotionally laden lore on top of gameplay as a reward for exploring and collecting things, the other offering puzzle rooms and rubies. So far into BotW, I think both games are on par gameplay-wise, but HZD would win any day for me, because of my personal preferences that call for what I mentioned previously.
I'm not sure if this conceptualisation is of any help to @heidegger or if it would offer inspiration for reconsideration of their perception of N games towards something more nuanced. At the end of the day, bouncing off the aesthetics of something so hard that you cannot see past it is, I think, a legitimate position, so there's no need to call anyone ignorant for that. Hell, I love the older Star Trek series, but I have friends who CANNOT stomach the aesthetics and the "laser guns" to enjoy the other elements in them. I'm not gonna call them ignorant for that, it's just personal preferences. Nor am I going to take personal offence because of that. Similarly, I have gaming friends who would skip everything to get to the gameplay and give zero fudges about aesthetics, who generally gravitate towards N way more than me. Again, not a question of maturity.
PS: On the topic of hide 'n seek, there's a certain mature-looking game of the previous generation which starts with a hide 'n seek tutorial. I'd be curious what @heidegger thought of that, especially if it didn't result in a similar reaction to Mario Galaxy.
Another excellent analysis! It's why I enjoy such threads, going deep on subjects is its own kind of fun :)
PS - what game is that?