https://www.youtube.com/watch?v=E5gVDDpviKo
Should you make all information available so that your readers know everything that transpired at the end of the book?
I am asking because there's this show called Evangelion and this show is almost impossible to follow at times, because some information are kept out of the audience's eyes and never ever shown, so piecing the story in its entirety from the available information is impossible, because some information are only made available on other materials outside of the show. Is this completely ok, and why would that be ok if it's ok, because I don't understand the point of doing that, except to frustrate your readers?