Solitaire Zero 21
Release date: Aug 28, 2025
Developers: NYX Digital Ltd
Publishers: Funbox Media Ltd
Genres: Casual
Categories: Single-player, Steam Achievements, Partial Controller Support, Steam Leaderboards, Family Sharing
Supported languages: English, French, Italian, German, Spanish - Spain, Portuguese - Brazil

Card game fit for all the family! The aim of the game is to clear the playing area of all cards whilst keeping your deck score between 0 and 21. If you hit 0 or below, or hit 21 or above, it is game over. Gameplay The player selects one of the top cards showing an addition or subtraction sum. This adds that card to their pile, applying the maths operation to their current score. The objective of the game is to stay within the range 1 - 20. If the sum falls to zero or hits 21, the game is over. Only the top items of each pile are visible, so the player needs to operate some strategic thinking in order to ensure they don’t “go bust”. Additional “wild” cards sometimes appear which has the ability for the player to alter their current score to help them (e.g. ‘MIN’ reduces their score to 1, ‘MAX’ increases their score to 20). When a player clears all the cards successfully without hitting 0 or 21 they win some diamonds. If a player fails, they can use their diamonds to try again where they left off. Player Control The game is controlled using either the Mouse or a DualSense / Xbox controller, to select the available cards with the thumb sticks to move a highlight around the screen, using A/X and B/O to select/deselect items as needed. Progression & Challenge The player works their way through the campaign, starting with Level 1. The difficulty increases as they progress. A player can also collect the diamonds to customise the pack theme. The game also features a Daily Challenge. In this game, all cards are laid on the table, with the player briefly able to see what they’re playing with. Then the cards turn over, and the player must select them one by one. Achievements The game features Steam Achievements as the user progresses through the game. These will be awarded for unlocking later stages of the game and completing certain levels within a time limit. Leaderboards The game also includes leaderboards to allow players to rank amongst their friends and the world. Leaderboards are progression and time based.