If you played Halloween, you do not need to play it again, you will not see anything new there. In the main plot - there are no new missions either. 0.3d is a New Years Event. If you want to open the entire gallery in 0.3d, then you will have to play Halloween, the main plot, and the New Year's event. But we always recommend our players not to chase the opening of the full gallery. The game is still at the development stage, and it cannot save the progress of the gallery when a new version is released due to the peculiarity of the engine.