Apart from a lot of Katakana English and a poster that says
Real world Japanese
There are some signs that are commonly used in Japan now as well. For example there is a back street with two signs:
駐 車 禁 止– the top part says no parking (I wonder who parked here the scooter). 通り 抜け 禁 止– no through road
There is a Japanese short curtain called のれん in one of the doors, that says おこしやす which is the same as the polite welcome phrase いらっしゃいませ, but in Kyoto dialect. In the animated short movie, the temple has a very clear view of Mt. Fuji. It means that it is not anywhere near Kyoto.
And a bonus…
This is not specific to Hanamura, but there are two characters on Genji’s armor
This is pretty well hidden and most people probably won’t even notice.
Hanzo is watching from the shadows.
If you have anything else you want to know, let me know in the comments. There are a few things I left out, like the sign of residential area, fire hydrant and a lot of katakana. There are probably some hidden Easter eggs as well!