This is a quite cerebral, and very interesting logic puzzle game, just like all other puzzle games by Conceptis.
The basic graphics and lack of music make for a pretty basic presentation, but that's okay, since we're not playing this game to look at a beautiful masterpiece, but rather to crack our brains. The lack of music also means I can listen to my own music while playing.
I really like this kind of puzzle game that relies completely on logic, because the solutions to the problems can be established deductively, like we were proving a mathematical theorem. I sure like how you can come up with quite complex puzzles from rules that are, in principle, very simple.
Also, I confess it took me some time to realize what to do from the rules made available in-game, I'd have changed them around to something a little more like this:
"The objective is to mark every square with either a circle or a shade such that:
- No two shaded squares touch each other vertically or horizontally.
- In every row and column, there are no two circled squares with the same number.
- The circled squares must form a contiguous area"
Overall, though, judging the game by merits of the puzzle concept, and the levels it contains, this is pretty excellent.