Picross LUNA 2 is a puzzle game with hundreds of levels, from the simplest 5-by-5 grids to the trickiest 20-by-20 ones. There are challenges adapted to all kinds of players.
Playing Picross LUNA 2 is simple: just tap the boxes you want to select or swipe over the screen to mark entire rows and columns. You can also select empty boxes easily, which should help keep you from getting confused. You can even change the control system if the original one doesn't suit you.
The several hundred levels are divided into a set of chapters that you'll have to gradually unlock. That said, from the start you can play puzzles on 5, 10, 15, or 20-squared game boards. In other words, from the get-go you should be able to find a challenge at your level.
Picross LUNA 2 is another excellent puzzle game that's back with an enormous number of levels, gorgeous graphics, and a relaxing soundtrack. One of the best Picross titles to be found on Android.