If you take a closer look during the underwater section of Koopa Cape (which is actually filled with water this time), you'll notice references to the underwater levels from NSMB, from both the Wii version and the DS port. Remember when if we raced at Koopa Cape as our Mii in Mario Kart Wii, our Mii replaces the Koopa Trooper seen on the wall ahead from the first jump? I wish that happened here.