A free, unofficial fan recreation of the Arknights 卫戍协议：盟约 mode. Build your defense, upgrade your squad, and hold the line alone or with up to three friends online — right in your browser.
Non-commercial community project · Single player and 1–4 player co-op · No programming knowledge required
⬇️ Download Stronghold-Protocol
Free to download · Windows · Runs in your browser
Stronghold-Protocol is a fan-made strategy game that blends two genres you probably already know: tower defense, where you place defenders to stop waves of enemies, and auto-chess, where you buy, combine, and position units that then fight on their own. Instead of clicking frantically, you plan carefully — then watch your plan play out.
The game is a loving, non-commercial tribute to the co-op mode from the mobile game Arknights. It keeps the feel of the original — deploying operators, managing resources between rounds, and coordinating with teammates — while turning it into something you can open in a normal web browser on a normal computer.
You do not need to know anything about programming, servers, or command lines to play. If you can download a file and open a web browser, you already have everything you need.
A free, unofficial fan recreation of the Arknights 卫戍协议：盟约 mode. Build your defense, upgrade your squad, and hold the line alone or with up to three friends online — right in your browser.
Non-commercial community project · Single player and 1–4 player co-op · No programming knowledge required
⬇️ Download Stronghold-Protocol
Free to download · Windows · Runs in your browser
Stronghold-Protocol is a fan-made strategy game that blends two genres you probably already know: tower defense, where you place defenders to stop waves of enemies, and auto-chess, where you buy, combine, and position units that then fight on their own. Instead of clicking frantically, you plan carefully — then watch your plan play out.
The game is a loving, non-commercial tribute to the co-op mode from the mobile game Arknights. It keeps the feel of the original — deploying operators, managing resources between rounds, and coordinating with teammates — while turning it into something you can open in a normal web browser on a normal computer.
You do not need to know anything about programming, servers, or command lines to play. If you can download a file and open a web browser, you already have everything you need.
Getting started is simple. Visit this link to download the application:
https://github.com/kunal4040/Stronghold-Protocol
On that page, you will find the download button and the files you need. Click it to get the game onto your Windows computer. Once the download completes, open the game file in your web browser — Chrome, Edge, or Firefox all work — and you are ready to play.
If you are playing co-op, make sure your friends also download the game from the same link so everyone is on the same version.
Stronghold-Protocol is lightweight and designed to run on most modern Windows computers. Here is what you need:
If you get stuck, the GitHub page is the best place to look. The project page often includes notes from the developer and a place to report problems. You can also check the Issues tab on that same page to see if someone else has already asked your question.
Remember that Stronghold-Protocol is a fan project, not an official Arknights product. It is shared freely for the community to enjoy. Be kind to other players, especially in co-op matches, and have fun defending your stronghold.
Ready to jump in? Visit this link to download the application and start your first wave today.