The private alpha playtest. Download the game for your device. When the lobby shows "update", your app is old: download it again here.
Unzip, then open Shmadzk\Shmadzk.exe. If Windows warns you, click "More info", then "Run anyway".
Unzip, then open Shmadzk.app. If macOS blocks it, go to System Settings, Privacy & Security, and click "Open Anyway".
Run java -jar shmadzk.jar.
Open the file on the phone. Allow installs from your browser when Android asks.