Two people have reported that they cannot start the Windows version.
After troubleshooting, we were able to get it to run by launching it with the command:
mule-online.exe --video-driver GLES2
From what I can gather, this suggests a graphics driver issue and a problem running Godot's OpenGL ES 3.0 rendering engine. However, because I and many others cannot reproduce this problem, I cannot be for certain.
In the next release (> v1.8.1), I will package a Windows BAT file to assist with this fallback, as well as making various other changes to potentially address this issue.
People encountering this issue are encouraged to post a reply here with your Windows version, GPU information, and anything else you think is relevant. Thanks.