Can refer to Ozymandias mocking his people, or the sculptor mocking Ozymandias
The ruler's heart
Feeding them - ironic, as the ruler is cold-hearted and offers his people nothing
The sculptor's art has survived Ozymandias, outlasting his political power
Look on my works ye mighty and despair: 'Ironic - Ozymandias intended this to celebrate his power, but now it celebrates the artist's power'
The reference to the Colossus of Rhodes is a double illusion - it suggests even mighty symbols of power get destroyed, but the Colossus itself was a myth that lived on