Animations are a bit better now than before but, on walk animation arms should swing opposite to the legs and on spell cast animations one leg should stay stationary on the ground and not slide (I also made this mistake before but, that way it looks much more natural).
Here is one Spriter animation test I made a while ago. https://dl.dropboxusercontent.com/u/104893773/C2%20Testit/Spektaakkeli2/index.html
Those animations started to twitch On one Spriter update.
attack C you can also make combo
Someone posted one animation reference site here some time ago http://www.referencereference.com/
Also there is quite lot reference animations on youtube.