A game like trivia cannot be rated with difficulty as knowledge is widely different for every person on this planet, depending on personal interest. It all depends on what you are interested in, for example i don’t watch Anime, but it ranks anime questions as easy or medium, as if most people would know these answers.
It’s basically just me nitpicking on the game, but i just find it a bit absurd to show difficulty ratings on trivia questions that could be about pretty much anything.