Sudoku: Classic & Killer

Four sudoku variants, five levels each, and no connection required. Every puzzle has exactly one solution, and every hint is built to protect the moment you work it out yourself. FOUR MODES - Classic — the 9x9 you know: rows, columns, boxes. - X-Sudoku — both main diagonals must also hold 1-9. - Thermo — digits rise strictly along each thermometer, from the bulb outward. - Killer — caged cells must add to the printed sum, with no digit repeated inside a cage. FIVE LEVELS Beginner, Easy, Normal, Hard and Expert in every mode. Level is set by the deduction the puzzle actually demands, not by how many cells are blanked out. HINTS THAT DON'T HAND YOU THE ANSWER Hints arrive in three steps: first the row, column or box worth a second look, then the single cell, and only then the digit. Stop after step one and the hint isn't spent. Beginner and Easy explain the technique in words; Hard and Expert stay quiet unless you turn explanations on. CHOOSE HOW STRICT THE BOARD IS - Block — an illegal digit simply won't go in. You cannot be wrong. - Highlight — mistakes are allowed, conflicts turn red. Learn by fixing them. - Off — the board tells you nothing. Just you and the logic. BUILT FOR LONG PUZZLES - Auto-save on every input, with a puzzle in progress kept per mode and level — up to 20 boards on the go at once. - Unlimited undo and redo, covering notes as well as digits. - Notes with automatic cleanup: place a digit and it clears itself from the notes in that row, column and box. - Cell-first or digit-first input, switchable mid-puzzle. - A remaining count on every keypad digit, and a check when all nine are placed. - The timer pauses itself when you background the app or open a hint. A PUZZLE EVERY DAY The daily puzzle rotates through the modes across the week and scales with your streak. Keep a streak alive with a freeze, or rebuild a broken one the next day. Long streaks earn a grace day automatically at every 30-day milestone. EARN YOUR THEMES Points come from solving — never from your wallet. Clean solves, no-hint solves and fast solves all pay more. Spend them on eight themes, from the Sunset the game ships with to Ocean, Lagoon, Forest, Lavender Dreams, Rose Gold, Midnight and Cherry Blossom, each drawn for both light and dark. Cosmetic only. There is nothing to buy and nothing to unlock with money. STATS WORTH KEEPING Best time, average time, win rate and hint usage, tracked separately for every mode and level. MADE TO BE READABLE Adjustable text size, a high-contrast option, a left-handed keypad in landscape, and independent toggles for sound and vibration. Full light and dark themes. YOUR RECORDS STAY ON YOUR DEVICE There is no account, no sign-in and no server. Saved games, stats, points, themes and your streak live in this app's own storage. On Android they travel with your system backup if you have one switched on — otherwise uninstalling the app removes them. PRIVACY No ads. No in-app purchases. No email, name or photo is ever asked for; your nickname is generated on the device. Analytics stays off until you agree to it, and you can withdraw that from Settings at any time.