I was wondering the same thing since I got into Rotate and Roll speedrunning right before the death of Flash Player. There were a ton of recent level records by Zambrini, and I found out that BlueMaxima's Flashpoint can emulate almost any flash game you can think of, including RnR.

Here's the download page: https://bluemaxima.org/flashpoint/downloads

I recommend downloading Infinity since it's a browser that let's you install the games you want. Hope this helps :)