Well, it’s actually a port of the mobile version of the game.
While the original Final Fantasy VI stood out to be one of the best, this one certainly disappoints. The graphics look simply terrible. Issues like flawed tiling, blurry filtering and resolution distortion are what makes it look so painful.
What we suggest that there are better-looking iterations on PSN or Nintendo’s Virtual Console. You can try out those until Square comes up something better. However if you are dead set on playing the official Final Fantasy VI PC version, then this one is your only choice.