can't play swf files with ruffle extension

Question

My kids have a lot of educational CDs, but the content is in flash format (.swf) and they can't read the CDs on their Chromebooks anyway.
I finally got tired of not having access to our content, so I spun up a web server and copied all the content over. Now they can see the files.
I've added the suggested Ruffle extension to Chrome to play flash content and turned on Allow File URLs. But when they click the file, it downloads instead of playing.
If you try to play the downloaded file, you get File type not supported. Drag'n'drop to Chrome just downloads it again.
I get the same behavior with flash files from Archive.org. You can test it here: archive.org/armorgames

I don't think this is a problem exclusive to Chromebook, since I get the same behavior on my laptop, with the Ruffle extension.

These are being served by Windows 2012 R2, IIS, with DirectoryBrowsing enabled.

Is there a better flash emulator, or any other ideas on how to play these?
Or is the only solution