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https://doondook.studio/games/new/zero21-solitaire/Scan QR code to play on mobile or copy link
Attract New Audience by This Special HTML5 Card Game!
Features:
- Age Rating: +
- Ready Levels:
- Level creator: Included
- Size: MB
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Zero 21 is a strategic, number-based HTML5 card game by DoonDookStudio that blends simple rules, focus, and smart decision-making into a relaxing yet challenging experience.
Players draw number cards and drop them onto the main card, carefully keeping the total sum between 0 and 21. Go above 21 or below 0—and you lose. It sounds simple, but every move requires attention and planning. Number-based solitaire games in this category have performed well on mobile platforms, demonstrating their appeal to puzzle and casual audiences.
With intuitive drag-and-drop mechanics and clean, easy-to-read visuals, the gameplay is simple to understand but difficult to master. Each level challenges players to think ahead, manage risk, and maintain balance while collecting all the number cards on the board.
Zero 21 Solitaire delivers engaging, brain-training sessions that combine the relaxing feel of solitaire with the excitement of number strategy—making it ideal for fans of card games, logic puzzles, and mindful challenges. This game’s similar version on Google Play has over 1K downloads.
Make Zero 21 Solitaire Uniquely Yours with Full Customization
DoonDookStudio’s customization services allow you to tailor Zero 21 Solitaire to perfectly fit your platform, audience, and brand identity. We provide end-to-end support, including reskinning, white-labeling, localization, and API/SDK integration, ensuring seamless adaptation to your ecosystem.
Launch your own customized version of Zero 21 Solitaire with your logo, branding, and preferred visual style—creating a strategic card experience that feels native to your platform and keeps players engaged level after level.
Click “Get This Game’s License” and share your vision for how Zero 21 should look and function. Our team will handle the rest and deliver a ready-to-publish HTML5 game.
Don’t forget to explore our game store for more high-quality, addictive titles built for licensing and full customization.
Zero 21 is a strategic, number-based HTML5 card game by DoonDookStudio that blends simple rules, focus, and smart decision-making into a relaxing yet challenging experience.
Players draw number cards and drop them onto the main card, carefully keeping the total sum between 0 and 21. Go above 21 or below 0—and you lose. It sounds simple, but every move requires attention and planning. Number-based solitaire games in this category have performed well on mobile platforms, demonstrating their appeal to puzzle and casual audiences.
With intuitive drag-and-drop mechanics and clean, easy-to-read visuals, the gameplay is simple to understand but difficult to master. Each level challenges players to think ahead, manage risk, and maintain balance while collecting all the number cards on the board.
...Zero 21 is a strategic, number-based HTML5 card game by DoonDookStudio that blends simple rules, focus, and smart decision-making into a relaxing yet challenging experience.
Players draw number cards and drop them onto the main card, carefully keeping the total sum between 0 and 21. Go above 21 or below 0—and you lose. It sounds simple, but every move requires attention and planning. Number-based solitaire games in this category have performed well on mobile platforms, demonstrating their appeal to puzzle and casual audiences.
With intuitive drag-and-drop mechanics and clean, easy-to-read visuals, the gameplay is simple to understand but difficult to master. Each level challenges players to think ahead, manage risk, and maintain balance while collecting all the number cards on the board.
Zero 21 Solitaire delivers engaging, brain-training sessions that combine the relaxing feel of solitaire with the excitement of number strategy—making it ideal for fans of card games, logic puzzles, and mindful challenges. This game’s similar version on Google Play has over 1K downloads.
Make Zero 21 Solitaire Uniquely Yours with Full Customization DoonDookStudio’s customization services allow you to tailor Zero 21 Solitaire to perfectly fit your platform, audience, and brand identity. We provide end-to-end support, including reskinning, white-labeling, localization, and API/SDK integration, ensuring seamless adaptation to your ecosystem. Launch your own customized version of Zero 21 Solitaire with your logo, branding, and preferred visual style—creating a strategic card experience that feels native to your platform and keeps players engaged level after level. Click “Get This Game’s License” and share your vision for how Zero 21 should look and function. Our team will handle the rest and deliver a ready-to-publish HTML5 game. Don’t forget to explore our game store for more high-quality, addictive titles built for licensing and full customization. see moreChange the games' theme, artwork, music, etc. so that they align with your business goals.

Buy This Game and Others for a 40% Discount!
Publish this game on 1 product
(website/app).
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Put your logo in the game.
A one-time purchase of the exclusive license to publish only on Facebook
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Change the games' theme, artwork, music, etc. so that they align with your business goals.
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With the “non-exclusive license,” you can use the purchased product for personal or commercial uses without paying extra fees or charges except for the initial purchase price. You can use the product for one project (app or website domain) of your own (personal, commercial, non-profit). You can not resell the purchased products again, not on their own nor as a part of a project. The purchased products under this license type must not be resold or redistributed “AS IS,” as a derived version, or as a part of a bundle of files.
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DoonDookStudio may, at its discretion, provide updates, upgrades, or fixes to the products at any time.
A supported product includes product support for 1 to 6 (depending on the products) months from the purchase date. During supporting time, DoonDookStudio is expected to be available to provide the product support services as described below:
DoonDookStudio owns the intellectual property of the products even after you get customized, changed, or white-labeled products unless we (DoonDookStudio & the buyer) have an agreement to the contrary.
You may need to use our products in more than one app/website domain or need more than six months of support. If you need a specific license type, please contact us with your requirements, and we’ll get back to you within a few hours.
By acquiring this license, you gain exclusive authorization to publish this game ONLY on FB Instant Games. To adhere to Facebook’s game publishing regulations, which prohibit the promotion of repetitive or duplicated games, this game will only be available to you and not to any other publisher on FB Instant.
“Games should be your own original creation and not mimic or copy existing games.” Facebook Game Quality Guidelines
It’s worth mentioning that the possibility of obtaining this license will be disabled on our website as soon as your order is confirmed.
We are dedicated to customizing your desired game (from our studio) from inception to publication. To accomplish this, we require precise details about the Facebook SDK features that you need, enabling us to provide you with a comprehensive quote and timeline.
Once your requirements are finalized and the volume of work and schedules are determined, we’ll issue an invoice. The game customization and preparation process will then begin according to your specifications.
The implementation of the Facebook SDK encompasses the following:
The cost of customizing the Facebook Instant Games SDK is determined based on your specific needs, in addition to the cost of the FB Instant license.
However, the license fee and 30% of the customization fee will be charged at the beginning of the project.
Our commitment to you extends throughout the customization process until your game is published on FB Instant. In the event of any issues or problems with Facebook’s approval, our team of experts will be on standby to assist you in resolving the matter.
Furthermore, the FB license includes a 6-month support period after approval, similar to a non-exclusive license. The support services will cover potential issues and bugs, as well as minor game modifications.
All of our games are unique and of outstanding quality, surpassing Facebook’s approval standards. However, if, for any reason, Facebook rejects the game, we are here to work with you to identify and resolve any issues that may have led to the rejection.
We will leave no stone unturned until the game meets the requisite standards and is approved for publishing on FB Instant.
However, if the game is not approved for any quantitative or qualitative reasons, don’t worry. In this particular case, your investment is protected, as the game license is refundable.