The formats are MP4 and MKV, and other file managers can preview them.
They play OK here. You may need to install codecs.
Make sure they play in the current Windows video player app (Microsoft keep renaming it in different versions of Windows, so I'm not sure what it will be called in your version) before worrying about Opus, since they generally use the same codecs.
Recommended codecs can be found here: HOW TO: Enable/fix playback of various media formats in Opus
Media Player cannot play, same error code, LAV Filters are installed, Seer or MPC player can play, I will use Seer to play.
I'm not sure if Media Player uses the modern video APIs or not. (It may, but it may not as well.) The best test is with the Movies & TV app (or similar, depending on name in your OS version).
Third-party players often include their own codecs, so they aren't useful except to check the video files can play at all.
If I turn off MKV or MP4 format in K-Lite, DOpus can play them, but the script log has some output: WaitLoad: 0x800700ea
Codec Tweak Tool
Not sure what caused that, here's another one.
Edit: Media Player still can't play them.