Rodensoft, a team of web developers and game creators, have created an “open world sequel” tech demo to Final Fantasy VII. It’s called Final Fantasy VII: Time Guardian.
They started by modifying the game’s source code but ended up creating this whole open world project instead as a way to “demonstrate how much power even the original FF7 PS1 engine has.”
As such, Time Guardian adds a number of new features to Final Fantasy VII, including full exploration of the game world, “a fully functional day and night system, shops that open and close, crafting of weapons/armor/materia, resource mining, house ownership, repeatable quests, character zapping/teams and a faction/karma system.”
It also stitches together a new story by resurrecting game files and backgrounds that were taken out of the final game. This included reviving quests such as the Kalm/Gongaga letter and finding out what Cait Sith gets up to when he is separated from the main party.
The team also managed to work it out so that you can change the main character at any time, create multiple parties to work in teams, and assigning individual skills to every character that can be levelled up at any time.
The video at the top of the article goes over all the features that Final Fantasy VII: Time Guardian boasts. Unfortunately, the game is no longer in development.