For sure gathering info is trickier than I thought. I've turned up indications SimCity and SimCity 2000 were available in Japanese.
By the way Imagineer has a helpful list of releases.
Hello there! Sorry for the late reply.
I decided to test to see if the game does not work on Windows 10 and, fair enough, it doesn't.
I tried using a compatibility mode, no luck. Like you said, it is working on a virtual machine. I tested it out on VMWare Workstation, using Windows XP SP3 Japanese.
As I was installing the program, I noticed the files it was installing. Most of them were .swf files (for backgrounds maybe?) and .flv files for video. Now, all of these files use the soon-to-be-deprecated Flash format, which is no longer compatible with most web browsers or newer operating systems. Maybe that might be the problem.
The only solution right now would be to play the game in a virtual machine or on an old PC with Windows XP or 7 installed on it.
Question for anybody versed in Flash: are there any other solutions to this problem?