Was this a port of the Flash app or reverse engineering it? The description on GitHub mentions that the Flash version was made by your friend, so I presume you have the original source available.

I've wanted to port an old Flash game for a long time, but I only have the .swf file, not .fla, because I'm not the original developer. I've tried several decompilers to examine the code and resources, but it would take a lot of work to make sense of the obfuscated code. Unfortunately, it can't be played in the Ruffle emulator since it is written in ActionScript 3, which is not currently supported.