I really think the short description gave you what you needed to know, but if not:

This is a re-write of the S4 battle between Twilight Sparkle, and Tirek; won't be focusing on the after-battle scene, nor the major build-up. This will take place from the point of the tree's destruction. I wanted to animate this, but I need time to practice in OpenToonz.

Though, dunno if "anime-style" fits the description; didn't make them monologue for 5 chapters.