It's been a while since I heard this one, but I pictured the protagonist as looking totally human from the neck down, and vaguely platypus-y from the neck up. Which is exceptionally freaky when you actually stop to visualize it.
Here's a little quibble I have, which might be entirely do to my poor memory: the protagonist was genetically engineered to be the way she was, right? So then she was born with a sense of smell that was vastly over-developed in relation to her sense of sight. (Maybe she just had really poor eyesight, but I remember her being totally blind.) If I'd never been a visually-oriented creature in my life, I think it wouldn't occur to me to have thoughts like "at least I didn't have to see the man's face."
But then, I don't know anybody who's been totally blind since birth; maybe I'm wrong.