Dark Sudoku - Classic Puzzle

Dark Sudoku is a Chrome extension that delivers a rich, logic-focused puzzle experience. Explore 15,000 puzzles across five difficulty levels—flash, easy, medium, hard, and evil—with a built-in editor to craft your own challenges. The dark, distraction-free interface helps you concentrate, while tutorials welcome newcomers and advanced players can use notes and Chains for sophisticated solving techniques.

Key features include a puzzle editor, camera scan for paper puzzles, two input modes, auto-fill, unlimited undo, eraser, per-difficulty statistics, leaderboards, and smart hints. This is a complete brain-training game designed for long sessions of thoughtful play.