"I have struggles in my life, but am I making a bland story about it?"
You could make a game with a bland story about your problems, and I wouldn't say, 'Ew,' because of your identity. I would say, if I wanted to be confrontational that day, "The story is trash, the themes are all sobby, and cringe, but at least, the gameplay is good."
If you look at the macro level, it sounds ridiculous to say Celeste stands out, but how many platformers with the same game feel, and similar art style polished to the same degree came out in 2017-2018? I don't personally know, but I'm assuming there wasn't any, and if there was, they were limited in number.
By game feel, I'm referring to animations (they influence how the game feels to play, they're bouncier in Celeste compared to other platformers), movement speed relative to level unit (blocks of 8 pixels, in this case), jump (height, length, cancellation, coyote time, buffer period), gravity (upswing, downswing), and a few others I'm too lazy to think of now.
You're thinking of the novelty of an element of the product on a far larger scale than the market did. Celeste has novelty to it in some of the places I mentioned before, so I won't concede it has no novelty on the larger scale, but most importantly, it was novel in 2017-2018.
Marketing began it's popularity, word of mouth carried it to the finish line, and why would you share a game if it wasn't good?
