I seriously do not know why devs don't just automatically include an in-built walkthrough guide and unlock all gallery scenes options in the menu, that anyone can turn on and off at their whim. There is zero reason not to, and it would be very helpful for those us.
He kind of already did that. The heartbeat sound means you picked an option she likes, sometimes there's more than 1 option she likes, sometimes there's only 1. If no heartbeat, click back, pick again, repeat til heartbeat.
Personally I think the need for a walkthrough in a game means poor design choices. There should be enough context in the choices to be able to make an informed decision OR there should be a built in ability to fix mistakes without requiring a reload or any kind of note keeping. Whether that's repeatable scenes or whatever doesn't really matter.
Consulting a walkthrough is very immersion breaking. I want to be able to just play the game, occasionally make a mistake, recover from that mistake without a reload and achieve the goal I'm after. Most of the choices in this game are obvious but sometimes you are rewarded for pushing your luck while other times you are punished for it. So there are some exceptions.
None of the choices in this game are very complicated and there are very few choices that have a consequence you don't find out about until significantly later. The main exception I can think of is the first gift you can buy from Chop Chop. Doesn't break anything if you pick the wrong one, but there is a clearly optimal choice that you don't see the consequence for until much later. Most of the choices have a consequence that happens either immediately, or soon enough that you can just click the back button a few times and fix it if you don't like the result.
As for gallery unlocks, I would personally find it annoying if the gallery was fully unlocked by default. I want to unlock the gallery by actually achieving the scenes that the gallery shows.