You've been able to play Sketch prototypes on the web for a few years already, also they just released a new iPhone app that lets you preview prototypes and docs. Their iOS Mirror app is pretty much deprecated now I think
Last I checked, I couldn't access the prototypes on a mobile device that wasn't iOS.
I just need Sketch to publish the prototype to a publicly accessible web URL like Figma does. When I needed to do usability testing, I had to use a third party service called Marvel that imports the mockups and publishes them to a web page on their domain.
