Stack The Deck · Black 4 Square
Privacy Policy
Effective 11 October 2026
This privacy policy is for the Stack The Deck game on Google Play, package com.Black4Square.StackTheDeck, and its web version. The developer is Black 4 Square, the name under which Daniil Denysov publishes games.
In short
- You play without an account: there is no sign-in, and your progress is saved on your device only.
- The game does not collect or send any personal information, and it has no online features.
- There are no ads and no in-app purchases.
- Nothing you do in the game is shown to other players.
- We do not sell or share any information about you.
Who we are
Stack The Deck is a game published under the name Black 4 Square. Black 4 Square is not a registered company: the game is developed by Daniil Denysov, an independent developer in Ukraine, who is responsible for this policy. In this policy "we" and "us" mean Daniil Denysov publishing as Black 4 Square.
This policy covers the Stack The Deck app on Google Play (application ID com.Black4Square.StackTheDeck), published by the developer account Black 4 Square, and the web version at carddeck.black4square.com. Contact: contact@black4square.com, Daniil Denysov, Ukraine.
What we collect
Nothing that identifies you, and nothing at all reaches us: the game does not talk to any server of ours, because there is none.
No account
Stack The Deck has no accounts or sign-in, no online leaderboards and no online features. It does not ask for access to your contacts, location, photos, camera or microphone. On Android the only permission the game uses is vibration, for the optional haptic feedback. The app's manifest also lists internet access, which the Unity engine adds to every app; the game itself never uses it.
Stored on your device
Stack The Deck keeps your progress (your deck, card levels and shards, the stars and best waves of the Grand Tour, your totals such as runs, wins and merges, whether you have finished the tutorial and the day you last opened the free daily pack) and your settings (music and sound volume, Auto Merge, vibration, screen shake, flashes, four-colour suits and the left-handed layout) on your device, or in your browser's storage in the web version. This information never leaves your device and we cannot see it. It stays there until you uninstall the game, clear its storage in your device's settings or clear the site's data. Settings → Reset Progress in the game also erases your progress.
The play log
To help balance the game, the Android app writes a small play log to a file on your device: when a run starts and ends, the venue and wave you reached, your lives, chips, deals and merges, the house rules you were offered and picked, and changes to your deck, card upgrades, shop exchanges and daily packs. Each entry has a time and a random session code that changes every time the game starts. The log contains nothing that identifies you, is never sent anywhere and we cannot see it. In the web version the log is only kept in memory and is gone when you close the page.
Technical information
The Unity game engine may send Unity anonymous hardware statistics such as the device model, operating system and graphics card. When you play the web version or open these pages, GitHub, which hosts them, receives the technical information any website receives, such as your IP address, browser type and the time of the request.
How we use it and why
Everything the game keeps stays on your device and is used only by the game itself:
- Your progress and settings: so you can pick up where you left off, with the game set up the way you like it.
- The play log: to help balance the game during playtests. It is never sent to us.
Who we share it with
We share nothing about you, because we receive nothing. These services are part of how the game reaches you and work under their own policies:
- Unity Technologies: the game engine. Privacy policy
- Google: Google Play delivers and updates the Android app. Privacy policy
- GitHub: hosts the web version and these pages. GitHub privacy statement
Other players do not see your progress or anything else of yours. We do not sell or share any information about you.
How long we keep it
We keep nothing about you. Your progress stays on your device until you reset it, clear the game's storage or uninstall the game; your settings and the play log stay until you clear the storage or uninstall. The play log drops its oldest entries as it grows, so it stays at about half a megabyte.
Your rights and choices
Because we hold no personal information about you, there is nothing for us to access, correct or delete. You can erase your progress in the game with Settings → Reset Progress, and everything the game keeps by clearing its storage or uninstalling it. If you have a question about your privacy, email contact@black4square.com; we reply within 30 days. You also have the right to complain to your local data protection authority.
Children
Stack The Deck has no chat, no ads and no purchases, and collects no personal information from anyone, children included. It uses playing cards and casino styling, but there is no real-money gambling: chips and shards exist only inside the game, cannot be bought and have no cash value.
Security
Your progress and the play log never leave your device, so they are as safe as the device itself. The web version and these pages are served over encrypted connections.
Changes to this policy
If we change this policy we will publish the new version on this page with a new effective date. If a future version of the game starts to collect any information, this page will say so before that version is released.
Contact
Black 4 Square (Daniil Denysov), Ukraine
contact@black4square.com