The developers for this game had a challenging task before them: doing something new and exciting with one of the most ancient, tried-and-true vodeogames in history.
I think they managed to do it: this is soothing. This is familiar. It's comfort food. It's Tetris.
You know how it goes: you play it and play it until, at some point, your mind just starts to wander into the flow, the tetrominos blending with one another before you, your fingers just moving on their own, your consciousness sort of disappearing in the background.
What I described is the titular Tetris effect. It's nothing new really, in fact it is as old as Tetris itself (so, at the time of this writing, 38 years old).
The distinguishing feature of this game is that it's really good at inducing said effect. Flashy, psychedelic background imagery, dynamic soundtrack that matches your movement, luscious particle effects. That's all it takes to make your mind completely wander after clearing a handful of lines.
It's quite surprising how these aesthetic choices are effective at creating this zen-like experience. Though sometimes the effects are a bit overdone, sacrificing clarity on the altar of aesthetics and psychedelics.
Apart from that, the game doesn't much, if anything, new with the mechanics of Tetris. There's just a little, kind of tacked-on "zone mode" that allows you to stop time and clear a lot of lines simultaneously. That's it.
And I figure that's kind of intended. This is Tetris, it doesn't need anything new to refine the formula.