Pretty much everything I ask for in an animated short. Especially the sound design/mixing and the background art. I've never played Dota, but nevertheless, I still found this awesome, which really demonstrates how solid it is.
I would criticise the stiffness of some of the actions here, and how certain poses could have been made more dramatic (like when she dodged the axe), but looking at your newer stuff, looks like that's kinda pointless. Either way, the timing and staging makes up for it.
The transformation sequence is my personal favorite moment- it's as if I'm watching a Tartakovsky flick.