Unlike almost every other rhythm game I and most people know of, A Dance of Fire and Ice is actually about your sense of rhythm rather than anything else.
It's fairly easy to think of rhythm games whose premise is "hitting a certain sequence of keys to the beat of the song". It's harder to think of games where your only objective is to keep up with the beat.

It's fairly intuitive, really. Just hit any button on your keyboard (or mouse) when the ball is about to land on a platform and you're good. But it escalates very quickly with offbeats, triplets, swing, and many other rhythmic concepts. All of which are borrowed from actual... You know, music.

Have I even TALKED about the visuals? This game is gorgeous!
The levels may start out fairly simple, but there's lots of eye candy buried in there, especially towards the second half of the game. Jungle City has tiles that grow to fill out the gaps between the gaps between the other tiles. there are these UFOs in Classic Pursuit that suck up the tiles you've passed through. Heracles has this big rat boss that you attack by going through tiles and launching them at him.

But the main selling point of this game is still the elegance. Telegraphing the patterns through geometrical shapes and the angles they make with each other is one of the best ideas I've ever come across. Because shapes are understandable. All of us can grasp shapes. We can all see them. That turns the rhythms and patterns which are vague and abstract ideas to most of us into easily digestible, mathematical forms in a way you don't even notice.

Also the music is great too, obviously.

This game is a visual and auditory masterpiece
Madeline feels great to control. She's snappy, the screen shake on her dash is satisfying every time, and all the information the player would need (Stamina, dashes, etc.) are perfectly telegraphed to them.
The respawns are instant and there's a checkpoint at the start of every new room. That keeps you from getting exhausted after every death because you have to stare at a 20 second loading screen.
Let's talk level design. A lot of difficult platformers acquire that title by requiring pixel-perfect precision and putting a lot of bs all over the place.
Celeste isn't like that. Not only are the designs natural and fit the theme of the level (e. g. Forsaken City, Celestial Resort, etc.) But don't require pixel-perfect inputs either. A large part of the process of getting through levels is solving them. Figuring out where exactly you have to go, in what order, and how.
The story also does a really good job of exploring mental health and trans identity.

Really the biggest achievement of this game was getting me (who rarely fully completes videogames) to 100% it, beat it around 5 more times and even attempt speedrunning it.
You KNOW it's special when that happens.