I checked my and your video and found interesting matter. There is no difference in opening movie or in game text. The difference comes from the text before each chapter. I will time the actual differences.

Your idea is interesting. But it turn out that there is no difference between RT and IGT. I timed from the final save of NG to the save after clear including some loads, movies and credits, then compared to IGT. Those times are literally the same. So using IGT doesn't work as you think.

I was curious about that too. I have a JP version ,so I can help you. What should I do? Or, if you run NG+, you don't have to care about that. In US/EU version you can skip some chapters ,so definitely faster than JP.

Hello. The moderator of the game "Calling" https://www.speedrun.com/calling has not been online for 4 month. I tried to contact but no reply. There is my pending run, and also I'm planning to run a new category in the game. So I would like to become a moderator. Thank you