This is three (or maybe four?) new episodes of the TV series, strung together and released on the big screen. If you're not a superfan, don't bother. The animation is certainly impressive, but the "plot" and "characters" are such thin anime tropes that it was painful to watch. Death scenes that turn into 20-minute monologues, combatants shouting out the names of their techniques as they execute them, winning and losing has less to do with skill than with the power of your determination, etc.

I'm glad my kid had fun, but damn I want that 2 hours back. If you've got a kid who wants to go, try to find a group of kids and get another parent to volunteer to take them.