"Justice League: Dark" is the second animated DC animated film with an R rating. It still didn't get an MA15+ rating in Australia like "Batman: The Killing Joke" did which in America was the first R rated DC animated film.
Guillermo del Toro has been producing (and originally directing) a previous live-action adaptation of the Justice League Dark comic book under the working title of Dark Universe. The animated film is based on an old script for Dark Universe.
In the comics, Wonder Woman's Lasso of Truth is able to cause anybody wrapped in it to see and understand the truth. However, when Wonder Woman is wrapped in it she cannot see through Destinys illusions.