Bloons Tower Defense 5 is a flash/HTML5 game made by NinjaKiwi. This was made possible by Ruffle, a Flash emulator made for emulating games that were made in Flash.
In your console/Shell, type "git clone https://github.com/oHeckGage/bloonstd5" (no quotes) and then wait for the clone to happen. Then, deploy it to whatever host you use such as Heroku or Railway or a separate VPS.
PLEASE NOTE: THIS WILL NOT WORK FOR A LONG TIME. RUFFLE DOES NOT SUPPORT FLASH AS3 (ACTIONSCRIPT 3) AND WILL NOT FOR A WHILE. MOST GAMES MADE AFTER 2006 WERE MADE WITH AS3, AND RUFFLE ONLY SUPPORTS AS1 AND 2. This flash game WILL work on the official Flash player however.