I think this would still be ~13 seconds faster than a DP2 with the buzzy beetle jump. If the yoshi block was just a little bit sooner, or the koopa stayed in the shell a little longer, it would be pretty fast & easy. Sometimes when the koopa flips the shell (0:32) it will kill itself, and im not sure if its controllable. might have to do with how you picked the shell up or put it down?