Despite his own concerns about the remakes taking up so much of his professional life, he says he's happy he took the plunge.
"Final Fantasy was one of the big inspirations for me to want to become a game creator in the first place," he says.
"This was my way of giving back to the series."
But he admits he's looking forward to doing something different.
"I want to move away from it an take on a completely new kind of challenge", he says.
"I've given everything I have to this."
Mr Hamaguchi says the game development climate when the first game was released means the approach to making the new games is fundamentally different.
Because it takes years to make a blockbuster game for modern machines, he says teams need to think about how the landscape will look in five to ten years' time.
For example, emerging markets such as the Middle East and South East Asia "are undergoing very rapid economic growth" and creating a new generation of gamers.
"It's really interesting to see so many young people getting into gaming in these regions," he says.
