I mean it’s your list and I haven’t played it but I find it hard to believe that a game that looks like it could have come out on the NES is the best game of the decade.
Likewise, it's your sensibilities, but there are so many different levels that I disagree with this.
Personally, I feel that things are only good if they're done in a way that holds up regardless of trends, and if something holds up, it doesn't really make any difference what era it could have existed in (and I disagree anyways, Celeste's visuals could not have come out in the NES era, not that it would matter even if it could). The best of the modern era isn't necessarily any better than the best from thirty years ago in terms of beauty, value, and appreciation, in my opinion. Baseline/average playability/fidelity is something that gets smoother over time, but those factors are superficial at best. The things that actually matter more or less stay just as unlikely/challenging to pull off regardless of era (concepts, design, execution, art direction, tastefulness, personality), and because of that, the actual peak value/quality of games aren't guaranteed to meaningfully improve over time, in my opinion (although you might get solid ones on a more regular basis). For example, I would consider Tetris a superior game over something like The Last of Us (which I find pretty mediocre and uninteresting), personally, and there are older games that I find more visually impressive/aesthetically pleasing than The Last of Us 2 as well, despite its obvious technological advantages.
In my view, it's no different from how music or films from before the 70s can sometimes be way better overall than things that get praised today (or say, how hand-drawn animation can sometimes visually look better than the cutting edge Pixar stuff-- Akira > The Incredibles 2, for example). It's not just better cameras/recording technology = better films/music.
On top of that, Celeste isn't an old game, so that give and take doesn't even exist. It fixes the superficial disadvantages of past eras that barely even matters in the first place, and great pixel art looks way better than ultra-life-like 3D, IMO. Ironically, the aesthetically ugliest part of Celeste is probably the high resolution portrait art,
which looks amateurish and not well drawn compared to the immaculate spritework, and I would argue that the story (which is still solid) holds it back for me more than the mechanics or visuals do.
