It tells a very light story but I liked what was there.
The core moment to moment gameplay consists of swimming around under water on some kind of alien planet. A lot of the creatures are obviously taken from earth oceans and the mix of familiar and alien is interesting.
Abzu wasn't a long game but I liked it. I played the whole thing in one sitting of about 4 hours or so and enjoyed my time with it. I would recommend picking it up for cheap on Steam sale whenever it hits a price that looks good to you.