Use https://github.com/ww-rm/SpineViewer if you want to view the animations (Note that you must have the .atlas, .json and .png in the same folder for this to work and edit the .atlas to support the .png in it).

Also side note for the Ninja creep when loaded in, it has two color variants in Skins being blue_fighter and magenta_fighter which when enabled will show its head and hands for the model.