MoonDoku: Sudoku Nights

MoonDoku: Sudoku Nights is a Sudoku game set in an observatory at night. Every day all players get the same Nightly puzzle, and each solve adds a star to the player's sky, where the stars gradually join into constellations. A cat sits on the observatory's window ledge and walks along the top of the board, reacting to mistakes and to streaks of correct answers; it can be petted and given one of eight coats. The game also includes 5,000 offline puzzles across four difficulties, ten switchable background worlds, an in-game lo-fi radio with optional ambient sounds, and an optional account for Nightly leaderboards.