The game seems to work fine using Ruffle, a Flash Player emulator. I have it installed on my web browser for cases just like this.
To try it for yourself, click here https://chrome.google.com/webstore/detail/ruffle/donbcfbmhbcapadipfkeojnmajbakjdc
or search for "Ruffle" in the Chrome Web Store
So, the short answer to getting the game running for your class again:
1. Submit approval for the download and installation of Ruffle to classroom computers
2. Download and install the extension (or desktop version if you please)
3. Go to the webpage and play (or download the game and distribute it to your students)