ECHO vs SudokuOS

Your echoes are your teammates. ECHO is a time-loop puzzle: every run is recorded, and when you press ECHO, your past self replays it - step by step, loop after loop. Hold plates for each other, open doors across time, and thread paths no single runner could ever take. EASY TO LEARN, DEEP TO MASTER - 100 campaign levels across ten decades, from gentle first steps to choreographed finales - Mechanics that weave together: chained doors, counter-doors, double doors, fragile floors, beat walls, paradox boards and mirror echoes that replay your run backwards - Handcrafted signature levels where every single step must be planned FOUR WAYS TO PLAY - Campaign: 100 levels with a carefully tuned difficulty curve - Daily puzzle: one fresh board every day - keep your streak alive - Zen: endless generated puzzles in six difficulties - Time challenge: how many boards can you solve in one run against the clock? MADE WITH CARE - Completely offline: no account, no ads, no tracking, no data collection - Music is synthesized live on your device - no two sessions sound the same - Home-screen widget that grows with your streak - and hides a secret level - Game Center leaderboards and achievements - Available in 7 languages ECHO is free and complete from the first minute. The only purchases are voluntary tips for the developer - they unlock nothing. Your past self is waiting.

Play Sudoku on your iPhone or iPad. Choose from five difficulty levels and solve each puzzle at your own pace. Use notes, fill in candidates for individual cells, get help from a hint or erase an entry. After completing a puzzle, view your rating and progress chart. Settings shows your solved puzzle count and best time. Your current game is saved automatically on your device, so you can close the app and continue later. Choose from six accent colours and adjust the haptic feedback setting. No internet connection or account is needed to play. The app contains no ads, in-app purchases or subscriptions.