I've watched this three times and it's one of those films that looks boring and generic, but actually turns out to be pretty good. The basic plot of needing to escort a princess really far away through enemy territory in a tiny airplane on a secret mission makes the early scenes very compelling. Several action scenes later, they're stranded on an island and doing survival things. Despite the slowness of this part compared to the first section, I still found the film enjoyable to watch. If you're looking for good films and have run out of Ghibli and Shinkai films, this one does pretty well in a pinch.