“Look on my Works, ye Mighty, and despair!” is a proud boast of his immense power
'Imetatravellerfromanantique land' - The poet distances himself from the statue and hearing about it second hand rather than by himself. The idea of an 'ancient land' suggests it is long forgotten.
'The hand that mocked them, and the heart that fed;'
Two interpretations:
Ozymandias is powerful and superior to his citizens
the idea of 'mocked' could mean replicated so well that he is able to bring out Ozymandias' true qualities to the people and the 'heart that fed' is the sculptor
'And wrinkled lip, and sneer of cold command' - no interest to help the ordinary citizens.
'boundless and bare' - Shelley uses the letter "b" as a plosive to emphasise the vastness and sheer power of this otherwise desolate desert.