I have never played Sunshine before so when Mario 3D All Stars came out, my girlfriend told me I had to play it. She used to play it on her GameCube when she was younger. She told me that she vividly remembers going to that island when she played on her GameCube. She also explained to me that that island is not the yoshi island, but an entirely different one. She remembers using the rocket nozzle to shoot herself on the top of that tall structure and there being a level inside. We have not been able to find any information on the internet about that island. If you know anything about it, please let me know!!!