Level 48 was the only one I had trouble with, it took me ~4-10 minutes just for that level. For those complaining about the ads, play in Airplane mode.
The game isn’t that difficult. Most levels are easy, some are moderate, and a couple can be hard.
If you don’t like the music, you can turn it off in the in-game settings.
I did have to use hints on some levels, however, unlike most games, they are free.
I beat it in ~20-25 minutes.
A RESET LEVEL button would be nice to have, instead of quitting and resuming.
My only “complaint” is no Game Center achievement for winning, otherwise I liked it.