Ruffle: Flash Player Emulator
Ruffle is a Flash Player emulator written in Rust. Ruffle targets both desktop and the web using WebAssembly.
There is a discussion on Hacker News, but feel free to comment here as well.
It played sbemail58.swf flawlessly, which I just so happen to have here locally (because of course). So it's feature complete insofar as I'm concerned! :)