0h n0 is a free puzzle game developed by Q42 for Android. It is the companion game of 0h h1 and follows its own three rules. The blue dots can see others in their row and column, and their numbers indicate how many. Meanwhile, the red dots block their view. The objective of the game is to complete the grid without guessing.

The game offers unlimited puzzles for all grid sizes including 4x4, 5x5, 6x6, 7x7, 8x8, and 9x9 boards. Players can play each puzzle in perfect Zen mode without any pressure. However, they can also attempt to beat their personal best time in the game's time trials, unlock fun achievements, and compete with friends in leaderboards. The game is free, without ads, without social network requirements, without locked features, and without nag screens.

Overall, 0h n0 is a lovely and challenging puzzle game that is perfect for puzzle enthusiasts. It is a great addition to the 0h h1 family and provides unlimited fun for all ages.