Thanks for the feedback! I'm very happy you enjoyed the game.
1) Rebel Duet has a set ending point. I plan for the story to reach its conclusion at the end of Act 7, although it's possible there might be 8 or 9 acts in total if I choose to split the final story arcs (as they're quite large in scope). Not sure how many updates in total this might be, but Rebel Duet is still a long way from being finished.
2) Free-roam segments is a good suggestion. It would make a lot of sense to have some free days where the player chooses where to go and who to talk to. I'll strongly consider adding this as a feature from Act 3 onwards, since all the main heroines will be available for romance then.
As for the scene gallery, this will be added in v0.9.
3) Sure, I could add more options to the settings for things like hairstyle preferences and character names.