Thank you very much for the kind words.
When the game is complete, we might make some add-ons or "special episodes" featuring other characters, yes! We have some ideas and some interest in that!
I can't say about an entirely new game, though. That's so far in the future, we haven't really thought about that yet.
We don't have any estimate for the next update, I'm afraid. But do feel free to follow RegalBuster on Twitter or join the Discord and you'll see development updates and notifications when we are close to release!