Thank you for dropping a comment! I would love to read your in-depth review. It's been so many years since the game's release and it makes me delighted that people still check out my work. On the other hand, I feel embarrassed about some elements of the game. There are many things I want to improve on- which will be highlighted in the DLC. Regarding your questions:
1) The whole story will NOT be changed. Both Roya and Chain's route follow the same plotline. You will view the story from their perspective and discover details never shown before. I did rewrite the prologue, but just changed minor details and order of events. The LIs from the main game will appear again and they have side roles. I changed the art, but the characters have the same personality and background story.
2) The DLC is going to be a new game file. I realized it's very complicated to program old and new elements in the same script. To make things easier, see this as a separate game. You have to start over because everything is new. The prologue alone has 5 choice menus.
3) I plan to add the DLC on Steam so people with Steam Deck can play it. Regarding a mobile app, I'm not sure yet. I have to figure out how to add it to the app store and import the files to joiplay. It takes time and I would appreciate any guides on how to do it. This whole project is run by 1 man, so please bear with me.
4) The old (main) game is forever available to download for free. I won't remove it from any platform. You can enjoy the old stories and art to your heart's desire! Upon many requests, I will add a patch with the new sprite art. In settings you can switch back and forth between old & new sprites. Old CGs won't be updated, so it may look a bit disconnected.
Thank you for the support!