It does give some back story to Froppy(Tsuyu), just like the manga but then it delved even further into a new story line that never appeared in the manga.
Pros: Still good new/fresh story, new quirks.
Cons: Tsuyu isn't the most interesting of characters' to get some background in.
~SPOILERS~
Only the very beginning of the episode about her parents and siblings are from the manga. Everything else is brand new a very cool quirk(zombie virus) that "acts exactly like in the movies," to quote Deku. Worth a minimum of one watch.
How can i write a longer review when this episode is only 21 min long and how long must it be.(5)