Importing into Blender, like I said above plays the animations but upon exporting as a .FBX it will lose all animation information. It is possible I'm doing something wrong here when exporting as I don't use Blender, but I've tried just about everything there is. I'll probably post on the Blender forums next.
I tried importing the GLB into many different 3d Modeling programs and none of them retained any animation information whatsoever on import.
Using Autodesk FBX converter converts the model but loses the animation.
Importing straight into Unity and GameGuruMax loses the animation as well. But really for best results it would need to be FBX in the first place.
Tried numerous online GLB to FBX converters, no luck.
Monster Mash uses vertex-based animation (i.e., keyframed animation of individual vertices of mesh) instead of the traditional skeleton-based animation. Such animation is exported into glTF format using Morph Targets which are converted to Shape Keys in Blender. The problem you're describing may be caused by exporters, which may not support Shape Keys; or the output format itself may not support vertex-based animation.
If the output format does support vertex-based animation, you can try applying Shape Keys for each animation frame so that the animation is "baked" into vertices for each keyframe.
An alternative approach could be to convert vertex-based animation into the skeleton-based one using some external tool like Dem Bones (https://github.com/electronicarts/dem-bones).