Nevermind, I guess I don't have a real problem after all.
The language selected at the top of the page is Language: English, the download URL has "en" in it (https://www.gog.com/downloads/iconoclasts/en1installer0
). but despite that, the file downloaded is "setup_iconoclasts_1.15_-_chinese_(24911).exe"
But I guess that isn't a problem. The installer was in English and when the game started I got to pick English and all's well. Nothing about this seems like Chinese other than the filename of the installer. Weird.
I wonder if some bits of content will be censored or uncensored or in a different color or something.