Really great! Simple yet fun, easy to learn but hard to master (kinda, or probably just me being bad).
There's nothing much to say about gameplay since it's mostly repetitive but it's a simple yet effective time killer specially if you're far away from your WiFi or no internet connection, meaning, yes it's offline. You can pay a dollar to support the developer/s and unlock the place called Dreamland with new music + designs(?), and the so-called "Zen Mode" which I don't know what the flip it does in this game. Lastly, the BGM is really great!
*PS: You can change the language you prefer since it has a decent amount. Which most 'whatever-language' you use will be in there, not really important but it's kinda nice not being locked to English even though pretty much the game doesn't use tons of words and will mostly be obsolete.