According to the game's producer and graphics/visual artist Daisuke Ishiwatari in a 1998 The PlayStation (JP) magazine interview, he was asked how the game's development started? He responded:

"Well, at the time we wrote the initial planning documents, the decline of 2D versus fighting games had not yet begun. And I personally felt like there was not a single fighting game out then that had truly “cool” characters in it, though I had been a fan of the original 2D fighting game, Street Fighter II. Anyway, feeling dissatisfied, I started drafting the plans that would become Guilty Gear. Arc System Works then publicly announced it, along with the characters, but there followed a very long period where nothing happened… eventually we reached at point at the company where we had a software development environment capable of handling it, and that’s when the real development finally started."
Contributed by ProtoSnake