Guessed by @S.Peelman
I'm a bit sad about dropping this game so far down the list in the past couple years, but I'm coming to terms with the truth that the position it used to hold, near the top 10, was never really right.
I think there are reasons why it used to be so high on these lists, namely all the holes it filled for me. I loved space shooters growing up, but could never really get my hands on one for long, and they usually weren't that good to begin with - this was amazingly good, and I could play it for as long as I wanted to. I loved sci-fi fantasy, but always wanted something space that was more fun and less serious, in comes Star Fox with its wacky characters and cheesy one-liners. And it came at a time in my life when I started allowing myself to get invested in fictional characters and appreciate the feelings they can bring to us. Meaning the time of my life when I stopped caring about whether something was 'childish' or not. That, and I just wanted something to spend all the time in the world with on my 3DS.
It's been a while since then, and many things have since come that can fill those holes. And it makes me realize, maybe Star Fox 64 just isn't what it used to be, for me at least. But it is still absolutely a great game, and I've many happy memories of my time with it.