The thing about the movie is that it's a continuation of the web series Carmilla; which, the series was streamed on YouTube. So my best advice for anyone who's going to watch the movie is that they should watch the web series first. Otherwise, it seems like it's not an adaptation at all.
Regardless, the movie does a great job of developing relationship problems and how characters work to figure things out. The goals they were trying to achieve were successful if you like the Carmilla web series you should like the movie :)