With the announcement that Steam is blocked in Vietnam I went looking for Vietnamese games to see what's out there. I found this. Unfortunately it doesn't seem to be available anywhere outside some sketchy abandonware sites so I found a long format playthrough to watch.
Supposedly this is the official website for the game:
https://7554.vn/
There also appears to be an archive.org link to it:
https://web.archive.org/web/20221001231815/http://7554.vn/
I couldn't download it from either source. Maybe I'll try later