It has that «alternate history / steampunk» look to it that was very common in anime as I was growing up, but eventually seemed to get replaced with cleaner and more modern designs, and I'm glad to see this sort of imaginative work back.
Take most of the singular aspects of The Way Way Back — the plot, a character, the soundtrack — and you'll not find them to be particularly imaginative, but throw them all together and it works in a way you just don't expect.