In a beach scene, some characters are shown in swimsuits. Nothing bad.

None.

Parasitic creatures lash out at and kill various people. Guns are used to shoot the creatures.

Fish are seen disintegrating.

1 use of hell

None.

Destroyah's final form may scare younger viewers.

The scene where the soldiers are fighting the soldiers is very intense, and may scare younger viewers.

People are seen running from Destroyah in the city, which can be quite frightening for young children. It is implied that many people are killed.