I'm not one for platformers, more of a tac shooter/city builder guy, but Celeste is honestly one of my favourite games. Even if platforming isn't for you, the story was great. It isn't overly long either.
I'm a bit torn on the story actually. I'm easily cringed, and some of the dialogue made me cringe. I also think the story takes a very individualistic approach to mental health. You need to overcome stuff yourself and so on (yeah there's Theo but he's just a barely relevant acquaintance). It fits well with the gameplay, but it's a terrible message.