That you for the kind words! I'm glad to hear that my take on the characters left an impression, even the original ones. When I was writing day 5 I had considered having the adventure continue; maybe some other crisis arises and you go on another quest with Cynthia to solve it, but I thought it was better to end it where it should end instead of dragging things out and having a story that's never finished.
I am definitely making more games like this, but a sequel/follow-up to Olivine Lights isn't planned at this time. I'm sure I'll write about Cynthia some more, but continuing this specific adventure with this specific protagonist would be tricky since there are so many little details with the different endings. I would have to pick one to be the "canon" ending and go from there, and that would be doing the rest of the story a disservice. So I'm sorry to say this but don't expect to ever see Unnamed-Guy-With-A-Metang again. His story in almost certainly finished.
I do have another Pokémon VN in the works, this one featuring Marnie. Most of it is written and I have a bunch of art commissioned for it, and I hope to have it completed and available to play before the year is over. I can't promise how long it'll take though. These things can't really be rushed.