C_Mill24’s review published on Letterboxd:
Once Upon A Girl subverted fairy tales well before Shrek. While Shrek was geared toward family-oriented audiences, this film here is just animated pornography, which has the issue of being difficult to rate in some regard considering its artistic implications. Not to say Once Upon a Girl is completely devoid of artistry, as some of the compositions of the film look quite nice, even if the animation is on a budget, in ways Hanna-Barbera and Walt Disney alumni can manage.
Yes, this was animated by former Disney and Hanna-Barbera employees.
If you're coming in expecting a clever subversion of fairy tale stories in a similar vein as Shrek, you'll find yourself disappointed, considering the pornography and sex. It's a film mostly played for laughs and you can find yourself laughing quite a bit at its blatant absurdity (witnessing a frog enter a woman's vagina and exit out of her mouth was not on the list of imagery I needed to see this year, but alas I have now). While the stories are certainly comedic and absurd, the pacing of some of the stories can be very taxing, particularly the Red Riding Hood story, where the repetitions of the sex scenes and unnecessary filler of Red Riding Hood pleasuring herself with a cattail or finding a troll guarding a troll bridge who laments his former lover running off with a "trag" (troll in drag). They're funny scenes in an absurd way, but they hurt the already rough pacing of the story.
If you're looking for a pornographic subversion of Mother Goose stories, Once Upon a Girl does a decent job at presenting a number of laughs through its absurdity. If you can forgive its repetitive moments and blatantly sexist portrayals of sex, you'll find a porn film that is decently entertaining, if particularly rough around the edges.