This is an RPG called(?) Final Fantasy: Unlimited Saga. There's already a dump available on the Internet Archive but I thought I'd do my own since I wanted my own copy anyhow. I did compare them and they aren't exactly the same. What has changed? As usual, no idea. The wiki does mention Sintax listing an English copy on their website so it *possibly* exists, but as far as I know nothing has turned up yet sadly. Thankfully the Chinese characters are all big and clear, making it easier to translate using a phone.
I do plan on playing this as it doesn't seem that bad so far. One random thing I did note is that despite being a Sintax release, there is no intro logo at all, it just boots straight into the opening scene (which you can't skip by the way :l).
Developer: 
Publisher: Sintax
Zui Zhong Huan Xiang: Wu Jin Sha Jia (最终幻想-無盡沙加)

The English version (Crystal Age) also had a listing on one of Sintax's Alibaba pages, meaning they did attempt to sell it at one point. As for the common dump of this game, my understanding is that is an early build that got leaked. Sky League had access to someone at Sintax who shared a few protos. This, to my knowledge, is the first time the final version has been dumped
Edit: And it was developed in-house. Could've started development under BBD I guess, but Sintax bought them out, so the distinction between the two isn't that important