You can move left/right by holding a/d keys to make the walk animation play.
https://drive.google.com/open?id=1iB4HO ... JTvypGlA82
I'm not exactly sure what is going wrong, the animation loops seamlessly in Spriter. Whenever it plays in game it looks to be starting half way through the cycle every time it loops. It's probably something simple, but I haven't been able to find anything online about it.