The Games
Every game on PuzzleProwl is built to the same standard — clean interface, mobile-friendly, free to play, and designed to get out of the way and let you solve. No paywalls on core gameplay, no dark patterns.
We're building one game at a time and doing each one right before moving to the next.
Classic Sudoku
Status: Live
The one that started it all, and still the gold standard of logic puzzles.
A Classic Sudoku puzzle presents a 9×9 grid divided into nine 3×3 boxes. Some cells are pre-filled with digits as clues. Your goal is to fill every empty cell so that each row, each column, and each 3×3 box contains every digit from one through nine exactly once.
No arithmetic. No guessing — every well-formed Sudoku puzzle has exactly one solution reachable through pure logic.
Difficulty Levels
| Level | Description |
|---|---|
| Beginner | More starting clues, straightforward solving techniques |
| Easy | Comfortable for casual players |
| Medium | Requires a broader set of techniques |
| Hard | Demands advanced strategies and careful tracking |
| Expert | For experienced solvers who want a genuine challenge — targets the minimum possible clue count |
Features
- Five difficulty levels from Beginner to Expert
- Daily puzzle — a new puzzle every day, rotating Easy, Medium, and Hard on a consistent schedule. Sign in to track your streak and share your result
- Puzzle library — hundreds of puzzles available on demand, with progress saved automatically so you can pick up where you left off
- Four-level hint system — hints that teach rather than just solve. Start with a region highlight, step up to a specific cell, get the technique name, or let the hint fill one cell and explain why
- Timer with pause — track your progress without pressure
- Pencil marks — track candidate digits as you narrow them down
- Undo — step back through your moves freely
- PWA support — install on your home screen and play like a native app on iOS, Android, and desktop
Core Solving Techniques You'll Learn
Naked Singles — a cell where only one digit is possible. The foundation of all Sudoku solving and the first technique every solver learns.
Hidden Singles — a digit that can only go in one cell within a row, column, or box, even if that cell has other candidates.
Naked Pairs and Triples — when two or three cells in a unit share the same two or three candidates exclusively, those candidates can be eliminated from the rest of the unit.
Pointing Pairs — when a candidate in a box is restricted to a single row or column, it can be eliminated from the rest of that row or column outside the box.
X-Wing — an advanced pattern where a candidate appearing in exactly two cells in each of two rows, aligned in the same two columns, allows elimination across those columns.
Classic Sudoku is the right starting point for any new puzzle player. Every technique you learn here builds directly into the harder variants.
Killer Sudoku
Status: In Development
All the logic of Classic Sudoku with an extra layer of deduction layered on top — and no given digits to start with.
Killer Sudoku replaces the pre-filled clue cells with cages — groups of cells outlined with a dotted border, each labeled with a target sum. The digits in each cage must add up to that sum, and no digit may repeat within a cage.
The standard Sudoku rules still apply — every row, column, and 3×3 box must contain each digit from one through nine exactly once.
What Makes It Different
The absence of given digits means you start with a completely empty grid. Everything you know comes from the cage sums and the logical constraints they create. This forces a different kind of thinking — less about elimination from given clues, more about what combinations of digits can produce a given sum in a given number of cells.
Key Techniques
Cage Combination Analysis — a two-cell cage summing to three can only contain one and two. A two-cell cage summing to seventeen can only contain eight and nine. Knowing these fixed combinations cold dramatically speeds up your solving.
45 Rule — any complete row, column, or 3×3 box sums to exactly 45. This allows you to calculate the value of cells that stick out of a cage into a unit, or deduce the sum of cages contained entirely within a unit.
Innies and Outies — cells that poke into or out of a region, whose values can be calculated directly from the 45 rule without solving the surrounding cells first.
Killer Sudoku is the natural next step after Classic. The jump in difficulty is real but the solving satisfaction is proportionally higher.
Samurai Sudoku
Status: Planned
Five Classic Sudoku grids arranged in a cross pattern, with the corner boxes of the center grid shared with the corner boxes of the four outer grids. One puzzle. 369 cells. A serious workout.
The overlapping boxes are the key — a digit placed in an overlapping box affects two grids simultaneously, creating constraints that ripple across the entire puzzle in ways that single-grid Sudoku never does.
What Makes It Different
Samurai Sudoku can't be solved grid by grid in isolation. The overlaps mean progress in one grid unlocks progress in another. Experienced solvers develop a rhythm of moving between grids — making small advances in each before the connections between them reveal larger breakthroughs.
Who It's For
Samurai Sudoku is firmly in intermediate to advanced territory. We recommend being comfortable with Classic Sudoku at Hard difficulty before attempting Samurai. That said, the puzzle's scale makes it uniquely satisfying — finishing a Samurai is a genuine accomplishment.
Kakuro
Status: In Development
If Classic Sudoku is a logic puzzle wearing arithmetic's clothes, Kakuro is the reverse — an arithmetic puzzle built on logic. Often described as a crossword built on numbers, it's one of the most satisfying puzzles to solve when it clicks.
A Kakuro grid looks like a crossword with numbers instead of letter clues. Black cells divide the grid into runs — horizontal or vertical sequences of white cells. Each run has a clue number in the black cell at its head. Your goal is to fill the white cells with digits from one through nine so that each run adds up to its clue, with no digit repeated within a run.
What Makes It Different
Unlike Sudoku, Kakuro has no box constraint. The entire puzzle is built on run sums and the no-repeat rule within runs. This creates a completely different solving rhythm — more arithmetic reasoning, more combination analysis, and a different kind of aha moment when a run locks in.
Key Techniques
Fixed Combinations — just as in Killer Sudoku, certain sum and length combinations have only one possible set of digits. A three-cell run summing to six must contain one, two, and three. Memorizing the most common fixed combinations is the single biggest accelerator for Kakuro solving speed.
Cross-referencing — where a horizontal run and a vertical run share a cell, the digit placed there must satisfy both runs simultaneously. Working these intersections is the core of Kakuro solving.
Min/Max Analysis — calculating the minimum and maximum possible sum for a run given its length and any already-placed digits allows you to eliminate candidates quickly.
Who It's For
Kakuro appeals strongly to players who enjoy the combination analysis of Killer Sudoku but want a different grid structure and solving rhythm. Prior Sudoku experience helps but is not required — Kakuro stands entirely on its own as a puzzle type.
What's Next
Our roadmap extends beyond these four variants. Puzzle types under consideration for future development include:
- Hitori — shade cells so no number appears twice in any row or column
- Nonograms — fill grids based on row and column clues to reveal a picture
- Nurikabe — a binary determination puzzle played on a grid
- Slitherlink — connect dots to form a single closed loop
- Futoshiki — like Sudoku but with inequality constraints instead of boxes
Have a puzzle you'd love to see on PuzzleProwl? Tell us about it. We maintain a running list of every suggestion we receive and genuine enthusiasm from multiple players moves things up the roadmap.
How We Build
Every game on PuzzleProwl follows the same development philosophy:
- Mobile-first — designed for smaller screens before larger ones
- No account required for core gameplay — open the page and play, nothing else needed. Sign in to unlock daily streaks, library access, and the hint system.
- Accessibility matters — high contrast support, keyboard navigation, and screen reader compatibility are not afterthoughts
- One game done right — we finish and polish each game before starting the next one. A half-built library of games serves nobody.
Follow our progress on our blog or get notified when new games launch.