a lot of rpg maker game have easily transferable save file keep this in mind for any other rpgmaker game(warning always back up, I don't hold any responsibility for any error) in yarimono case go to data->www->save. just copy and paste it to the newer version.
this development room on top of your house, you can reveal the ladder by interacting the spot mc is looking at 5 time. just keep going until you see a room where you can see different cg (think of it as second gallery) and then go to the bottom right
this development room on top of your house, you can reveal the ladder by interacting the spot mc is looking at 5 time. just keep going until you see a room where you can see different cg (think of it as second gallery) and then go to the bottom right