I'll watch the video tomorrow, but I have great memories about Galaxy.
When I first played Galaxy, I was not expecting much more other than a 3D Mario game(I played it in 2011 or so). I was wrong. It was much more than that to me and one of the very few games that truly brought me back to that justified nostalgia feeling. Keep in mind I played this one when I was 13-14 years old, so I was not a player during the 3D platformer* boom and, what's more, I didn't even play Mario 64 or Sunshine before Galaxy. It really felt like I was playing something very special, even magical. The game flowed so well, the level design, the music, the challenge, the colors... I haven't touched this game in years and I'm afraid to do it so again because I want to keep remembering it as I was feeling it back then.
What's funny is I also own Super Mario Galaxy 2, but I didn't get throught that one for more than 5-6 levels. Not because I didn't like it; I loved it. It's just that I've been keeping it as my wildcard game for whenever I want to get that feeling back. These games, even if they were platformers dressed up in Super Mario skins(which they're not) are something very special to me.
*This reminds me that I don't recall beating any 3D platformer until Galaxy... I don't remember if I liked 3D platformers at all, except one of the Rayman games and, if we count it, Sonic Heroes LOL Spyro, for example, seemed pretty lame to me when I was a child.