This is a puzzle game with a UI that is well-suited for a touchscreen. I did pay for the DLC that removes ads (I almost always do this).
The puzzles are all very well designed. There are several groups of levels that have some nice variations. For example some types have new bubbles constantly being added so there is that element of randomness being added. And others are very carefully designed to play a specific way, even requiring careful timing as the bubbles collapse on a few of them. On a few of the levels I got impatient and used the hints. In general, as I played the game I would become tired of it after 6-8 puzzles (30 minutes?). I think that is fine, as this allowed me to kill time on many different occasions and I always enjoyed playing those 6-8 rounds until I tired of it. Maybe it means that the game was mentally stimulating and tired me out.
There is one mechanism throughout the game where two bubbles of different colors combine to make a third color of bubbles. In the normal color mode I believe it is pretty intuitive how they combine, for example yellow+blue=green. Unfortunately I am color-blind and I had some challenges with the normal color mode. Fortunately is a colorblind mode and those colors are easy for me to distinguish. Unfortunately then the colors don't combine very intuitively, for example white+yellow=darker yellow. After a while I just memorized the combinations, so it isn't a game-ruining issue.
I could maybe see myself replaying some levels in the future. There is an Infinity mode where you get some moves every few hours. I did a couple cycles of this but wasn't that interested. This is probably a mechanic to drive you to purchasing micro-transactions. I almost universally avoid those.
There are achievements; I don't have any desire to finish them out.
