I don't think I've ever seen an anime differ so much from the original source just like this one. It's not just missing some scenes, it's changing the entirety of how the scene happens. Adding in more scenes for anime-only content is fine to a point but the way they did it this anime was just... unnecessary. They skipped and changed so much stuff that it's quite disappointing. And how they ended it... wth. Do yourself a favour and read the manga/manhwa/wtv it's called. You'll enjoy it more. The series can be enjoyed on its own if you've never read the original source.