About This Game

MoonDoku is a cozy sudoku for the end of the day. Solve tonight’s puzzle and it becomes a star in your sky; keep coming back and your stars draw constellations. There’s a cat for company, a lo-fi radio under the rain, and five thousand more puzzles whenever one isn’t enough.

The Nightly is one board a night, the same for everyone who plays it. Every star you earn stays for good, and your stars join up into constellations, seven to twelve nights a figure, with four to choose from each month.

Missing a night never undoes a drawing; it waits for your next star. A board finished past midnight still counts for its night, and a star placed under a full moon shines a little brighter.

Five thousand puzzles come with the game: 1,500 Easy, 1,500 Medium, 1,250 Hard and 750 Expert, with no repeats until a difficulty runs dry. Each has one solution, reached by logic alone; Expert asks for pointing pairs and subsets.

There are no pencil marks. Every number is checked the moment you place it: right answers lock in, wrong ones clear themselves, and the first slip is explained. You get three hearts a board and one to three hints by difficulty. On endless boards the clock never touches your score, so take your time.

Between games it sits on the observatory’s window ledge; while you play it walks along the top of your board. Click to pet it; right-click, or click and hold, to change its coat. There are eight, from a plush gray Chartreux to a longhaired Ragdoll.

It reads along as you move with the keys or a controller, winces at a wrong number and slow-blinks after twelve right ones in a row. Leave it be and it nods off where it sits.

Nine worlds wait outside the window, from falling cherry petals to rain, fireflies and shooting stars. Click the brass arrows beside the porthole, or tap the bracket keys mid-puzzle, and the whole game repaints to match.

MoonDoku FM has three stations (Chillhop, Lo-fi Jazz and Downtempo), and you can mix sounds over them: café, rain, fireplace, ocean and storm, each at its own level, all offline.

When you want just the board, press F. Focus dims the room around it while the music plays on, and F brings it all back.

• Offline. All 5,000 puzzles live on your drive, no account needed. The Nightly comes from the server, so it needs a connection.

• Steam Cloud. Your sky, your streak, your cat’s coat and a half-finished puzzle follow you between machines.

• Keyboard, mouse or controller. Type digits, click the pad by the board, or use a controller’s 3×3 picker.

• 17 achievements, from your first Easy solve to a thirty-night streak.

• An optional free account. Sign in with an emailed code to see where your Nightly time ranks.

• One purchase. No ads, no in-game store, nothing sold separately.

• Windows, macOS and Linux.

Put the kettle on. The board’s ready.

AI Generated Content Disclosure

The developers describe how their game uses AI Generated Content like this:

Some of MoonDoku's art and audio was made with generative AI tools while I built the game: the animated world backdrops, the MoonDoku FM music, a few sound effects, parts of the store and icon art, and a handful of smaller in-game images. I directed, edited, and composited all of it by hand.

Everything else is made without generative AI. The puzzles come from my own deterministic generator, the cat is a commissioned 3D model I animated in Blender, and the game design & layout are directly from my brain.

Nothing is generated while you play, and the game never talks to an AI service.