Logic stays on device.
Core Sudoku sessions, settings, world presentation, and local progression are designed to remain meaningful without a mandatory sign-in flow.
Offline Sudoku game / Android design
A quiet board should remain
A quiet board should remain
available between connections.
An offline Sudoku game should not ask a player to negotiate with an account or a server before returning to an unfinished board. Sudoku Cosmos is designed around local core play, local progress, and a player-controlled Recovery Vault transfer path, while staying explicit about services that do require a connection.
LOCAL•OFFLINE CORE•PLAYER CONTROL
Transfer is player controlled.
Recovery Vault uses an encrypted export, a chosen PIN, and a recovery key. It is not a cloud account or a shared-family save service.
Connections remain named.
Official store delivery, updates, optional rewarded advertising, web pages, and public sharing naturally rely on external systems and should never be described as offline core play.
Offline Sudoku FAQ
Does offline-first mean every feature is available without internet?
No. It describes the core Android puzzle and local-state path. It does not turn websites, store delivery, or optional ad rewards into offline services.
Is the web sample an offline Sudoku game?
No. The web sample is an online browser demonstration of classic 9×9 Sudoku. It is deliberately separate from the Android offline-first product claim.
Why not force an account for progress?
The product preference is local continuity first. Device change is handled through a player-controlled transfer rather than mandatory account creation.