The bare-breasted prostitutes were not put in the film to make it more risqué, but rather to add a note of historical authenticity. Venetian law at the time required all prostitutes to bare their breasts because the Christian authorities were concerned about rampant homosexuality in their city.
Approximately 0:02:50 into the film, camera equipment and a man with a black baseball cap w/white logo are seen on the left hand side of the frame. It's a very quick cutaway scene after a couple shots of the white balcony.
When Basanio and his entourage are walking with Portia to inspect the chests they pass a pond with a black swan. Black swans are from Australia and weren't known to Europe until after their discovery in western Australia by Dutch explorers in 1697. The Merchant of Venice takes place more than 100 years earlier.
Portia: The quality of mercy is not strained, it droppeth as the gentle rain from heaven upon the place beneath. It is twice blessed - it blesseth him that gives and him that takes. 'Tis mightiest in the mighty. It becomes the throned monarch better than his crown. His sceptre shows the force of temporal power, the attribute to awe and majesty wherein doth sit the dread and fear of kings. But mercy is above this sceptred sway. It is enthroned in the heart of kings. It is an attribute to God himself and earthly power doth then show likest God's when mercy seasons justice. Therefore, Jew, though justice be your plea, consider this. That in the course of justice, none of us should see salvation. We do pray for mercy and that same prayer doth teach us all to render the deeds of mercy. I have spoke thus much to mitigate the justice of your plea,
What changes have been made from the original play?
A
Two notable ones :1) Antonio, the merchant, is actually shown onscreen spitting at Shylock, the moneylender, at the very beginning, before the plot has even begun to develop. This serves to make him notably more unsympathetic than in the play, in which he treats Shylock more or less courteously until he is put on trial.
2) The relationship between Bassanio and Antonio is clearly homosexual, while in the play it is more ambiguous, even innocent. There is even a moment in the film (not in the play) in which Portia indicates by a look and the tone of her voice that she clearly understands that Bassanio and Antonio are former lovers.