Well I was thinking more about a campaign style, where you could only later play levels once you get at least one star on the level before that, or you could have a system where you would need a total of say like 5 stars on the first 3 levels to gain access to the fourth, or maybe when you get later in the game you unlock more cool traffic signs/resources (like the yield sign if you were to implement that, or just QoL tools)?