It seems like I'm your tester for the webwidget 8)
Anyway a week ago I wanted to display a spider fella I made for last year's jam, and I made it by creating one leg and then duplicating it 7 times, funny thing is in the editor and skeletonViewer it works, but in the webwidget only one leg moves.
Here's the link: http://www.erikari.it/GGJ2017/spine/spider.html (all his legs should be dancing)
Spine widget only animates one leg
- Editado
Actually, poor Spider dude doesn't work in the latest SkeletonViewer either http://www.giphy.com/gifs/26xBSycVPbUKnvEpq
Can haz Spine project file?
Sure! I emailed it to your usual contact mail (:
For anyone else with a similar problem: turns out I just had to re-save my old project in a new Spine editor version because the spider was made in 3.0 or so and then it magically works again 
Shit happens 
Thanks for your diligence and the repro case!
Good catch!