Going into the code and disabling the assets the developers left in the background, other than that, no.
Japanese games typically don't do that, at best they get what this one did, translated text. The exception would be huge games with a legitimate international following, where the original developer then sees further opportunity if they contract out to a western company to dub it.
With a developer like Illusion, they are just getting started in the western market, this was only their second game to be sold outside Japan through Steam and third total. They aren't exactly a big developer, so they may not even have the funding and that puts them in an even worse position where they have to be even more selective about what they do and don't do. We're lucky we even got it with English text.