Definitely sandbox. There's a heavy focus on "tell your own story" and using your imagination in 4. They give you a base with vague concepts and allow you to tell your own story from that, whilst in other games there was a lot more things that just happened and directed gameplay. In Sparkd they labelled their players as either storytellers, builders, or stylists and I think that's how they see their players - content is made to allow players to make their own stories, build and make sims