The following info comes from a Kotaku interview with director, Atsushi Hashimoto...
“The story focuses around the protagonist and his friends. They awaken a power within themselves to fight against this phenomena. What we’re trying to do is basically use the base of the Japanese RPGs from the ‘90s, the Golden Age of RPGs and use modern game technology and development methodology to enhance new JRPGs with that core.
We got a lot of feedback from people who played I Am Setsuna, and they said they were feeling a little limited by the fact [that they couldn’t move around]. We did a number of experiments, and then we decided to be able to move characters freely was the best approach.
If you found a certain way of defeating enemies [in I Am Setsuna] you could keep repeating that one winning formula, and it could maybe get a little stale. This time around, we give the enemies more depth to make them something you can really sink your teeth into. Rather than making them harder, give them more damage, we decided to make sure that you have to really think about how to beat each one separately.”
For Lost Sphear, what you’ll see is a world that’s made up of different cultures. There’s a machine-based culture; there’s a magic-based culture. You’ll see how these cultures mix and track with each other, and that’s led to a much more varied world—there’s a lot more variation this time.
We didn’t set out with the idea that we’d take inspiration from Final Fantasy X and make a similar story. We set out to make a story we felt was interesting and what we wanted to do. In the end, after we made it, we said, ‘Hang on, yeah, we have made a similar tale in some ways.’ So this time we’re not setting out to make a game based on a particular preexisting Final Fantasy story, but there is very much that chance that when we’ve finished it, it’ll be a bit similar to something else.
Originally we were aiming to make it the same length [as I Am Setsuna]. Ultimately it’s worked out to be a slightly longer game. It probably will take you about 30 hours.
We did a lot of experimentation to find out what would work well for this game and make it different than Setsuna. For Setsuna, we pretty much concentrated on those depictions of snow scenes... This time we got to branch out a lot more, work out how to best depict other things, give the right feel and impact. We really had to think very hard about how to do those other things as well, that maybe Setsuna couldn’t so much.
One big reason we wanted to put the game on Switch is that we like that it can fit into different gamers’ lifestyles and patterns, and they can find the best way of playing for them. The other thing is that the technical capabilities and specs of the Switch fit very well with the type of games we’re trying to make at Tokyo RPG Factory.
I really want to talk to you about all the details, but I can’t mention so much. There’s a lot of little things we’ve added. Even within different dungeons, there’s gonna be a lots of little changes.”