Zero21 Solitaire

📂 Game Profile

• Title: Zero 21 Solitaire
• Genre: Puzzle / Math Card Game / Logic
• Platform: HTML5 (PC & Mobile Browsers)
• Target Audience: Math whizzes, Sudoku fans, Logic lovers, Brain trainers
• Core Experience: Mental Math, Anticipation, Crisis Management

📜 Description

Zero 21 Solitaire is a minimalist number puzzle game. The interface typically consists of your "Current Sum" in the center, surrounded by three (or more) stacks of cards.
Your goal is crystal clear: Clear all the cards from the board. However, there is one fatal rule—at all times, the sum in your hand must remain between 0 and 21. It’s like walking a tightrope; go one point over or under, and you fall. You must maintain this delicate balance through precise calculation.

🃏 Gameplay Mechanics

Simple rules, zero margin for error:

• Add & Subtract: Cards are colored Blue (Positive, e.g., +3) and Red (Negative, e.g., -2). Tapping a card adds that value to your "Current Sum."
• The Danger Zone:
  • If the sum exceeds 21, you lose (Bust).
  • If the sum drops below 0, you lose.
• Special Cards: To help you out of tight spots, there are utility cards:
  • Reset (R): Resets your current sum to 10 (or a neutral number).
  • Divide (÷2): Cuts your current sum in half.
  • Swap: Switches the order of cards in a stack.
• Stack Mechanics: Cards are stacked. You must use the top card to reveal and access the cards buried underneath.

💡 Strategy Guide

It's not just arithmetic; it's resource management:

• Hoard the "Antidotes": Don't use up all your Negative (Red) cards early! When your sum nears 21, a negative card is your lifeline. Conversely, save Positive cards for when you are dangerously close to 0.
• Balance the Flow: Try to alternate between positive and negative cards. If you take a large positive (+8), try to follow it with a negative (-5) to neutralize the gain and keep your sum in the "safe zone" (around 10).
• Look Ahead: Don't just look at the top card. Peek at the cards underneath. Calculate: "If I take this top card, can I handle the one below it?" If a +10 is buried and your sum is already 15, you cannot afford to uncover it yet.
• Save the Reset: The Reset card is your ultimate safety net. Save it for the moment when no combination of addition or subtraction can save you.