This is one of my favorite games of all time. Before I gush about it, play it if you haven't already I can't recommend it enough. It's one of the most unqiue 2D platformers you'll ever play and is 100 times better then most triple A games released.
What works in this game is how the story and gameplay work off each other. This game is presented as a pretty difficult 2D platformer that encourages you to fail and learn. Madeline is tasked with climbing mount Celeste and as she struggles with her anxiety the platforming reflects that. Sometimes the levels introduce a random boss, difficulty spike, or moment where things get tense but this perfeclty reflects in Madeline's emotional state. There's a ton of symbolism and themes that just elevate this game. Along with that the game is just straight up fun and diffcult in all the right ways.
My only issue is with the golden strawberries and wall bouncing. I think the golden strawberries directly contradict the games themes since the game always encourages you to fail and yet this challenge discourages failing. Lastly I suck balls at wall bouncing.
Overall, an excellent game and easily one of my favorites.