I literally just changed one platform in Fossil Falls to a semisolid because I felt like it :P It's the platform with four coins on it btw
In case no one has noticed from my projects and the collabs I'm part of, there will never be a Mario game I make/help make that won't have semisolids because I know three different methods to add them Just add the top pixel layer as the semisolid part and only collide if y speed is less than 0 and the bottom sensor is touching the semisolid sprite