Ni no Kuni

The art looks a bit alike . Also Haku and Yu looks alike as well. Both stories contain amazing fantasies . Ni No Kuni is isekai and spirited away isnt isekai but its kind of alike in a way , both stories are about an unusual place with supernatural powers and fantasy related stuff . If you liked spirited away , you'd probably love this as well .  

both movies are about one or two characters going into another world ( the way to get to it is different in both movies ), said other world is a fantasy world where stuff like kings and princesses exist, the main girl is a princess in the other world in both movies too maybe not exactly top tier anime movies imo but they're both alright for what they are, isekai anime movies, yes i know Napping Princess isn't classified as such but it's still isekai to me  

both deal with alternate worlds and dimensions  

they both have very similar plots about two or many worlds and friends who are trying to save the person they love.  

When two friends fight for a princess (fighting for a girl they both love) Making one of them a villain of the story both have suspense, drama, and many more you can ask for in a series or a film. I highly recommend both if you haven’t watch them. 

Both are movies that follow two “friends” who travel to different worlds, fantasy RPG-styled. Both sets of main characters have different ideas of how to solve the main conflict and end up traveling down separate paths, good vs evil, as a main plot point. Additionally both movies are also based off of video games.