The official Japanese website for Crisis Core: Final Fantasy 7 - Reunion says that it is "greater than a mere HD remaster" and gives a bit more detail on what the remaster entails.
During the 25th Final Fantasy 7 anniversary stream, one of the big surprises from Square Enix was a Crisis Core remaster called Crisis Core: Final Fantasy 7 - Reunion. Although it's a remaster, many thought that it might actually be a remake thanks to how improved the graphics are. As it turns out, the Japanese website for Reunion seems to think it's much more than a remaster too.
Related: Final Fantasy 7: Crisis Core Isn't Perfect, But It Still Deserves This Remaster
Following the announcement of Crisis Core - Reunion, a website for the game was posted online by Square Enix Japan, which reveals a little more about the game through a description page. Unfortunately, even a few days after the presentation, the website still doesn't have an English version. Thankfully, Twitter user aitaikimochi has translated the "about" section of the website to reveal what it says and making it clearer what Reunion actually is.
According to aitaikimochi's translations, this is what the page says, "Crisis Core: Final Fantasy 7 is a heartfelt story that was released in 2007 and since then has become a highly acclaimed part of the series. The story itself is connected with Final Fantasy 7, and now through time, is revived with utmost quality."
The description also confirms that the game replaces the original models with new ones, but seems to keep the same animations, "By incorporating the latest HD graphics, all characters in the game will get a completely new 3D model. Amidst a story full of turmoil, the game will also be fully voiced and contain newly arranged
Read more on thegamer.com