Then use jump+circle to destroy the boat. Then press X only, don't double tap or press any direction in order to rip off Gomora's little horn.

After that your power meter is full and use Ultra Saw Disc to cut off Gomora's tail. Let Gomora goes to near Osaka Castle, SSSP will shoot Gomora. Remember, never let you or Zetton destroy the SSSP base. After Zetton defeat you, Zoffy arrives and beat Zetton in ASAP.

First use counter attack (block and attack) and build up your meter to use Ultra Bind Ring, Saw Disc, and Specium Ray in order. However, I will tell you the easy way to get S rank. Because of Zetton keeps attacking you without leaving any chance, it will be hard for you at fist. First, Zetton will keeps attacking you and don't let you destroy SSSP base or it will be mission failed.