GODZILLA DOMINATION UNLOCKABLES
Monster Island from Godzilla Destroy All Monsters Melee
By playing with Godzilla or Mothra in story mode. Finish all eight levels to see the ending sequence. When you finish all eight stages, the background will resemble the Monster Island level from Godzilla: Destroy All Monsters Melee on the Gamecube.
How to beat Mecha-King Ghidora
Use King Ghidora. As soon as the match starts and it roars three times (one for each head), jump and push B (multi kick). After Mecha-King Ghidora freezes, attack the light on its chest the same way. When Mecha-King Ghidora attacks you, do not dodge (just block) unless it jumps. Once it finishes, repeat the steps above until you destroy each head. REMEMBER: Try not to use special attacks -- they are not very useful.
King Ghidorah Keep Air Kicking
By playing with King Ghidorah and jump by pushing R. Press and hold R then push B to kick. If you keep pressing and holding R and tapping B, you will stay floating and kicking. When fighting with King Ghidorah, you do not have to press and hold R to do his floating multi kick. You can just tap B and you will float after jumping.
Float
As Mothra, Rodan, or King Ghidorah, press and hold R to jump and float down more slowly. REMEMBER: This works especially well on the Moonbase level.