Danielle De Luca's performance.
Whether you liked the movie or not, you have to admire Danielle's fortitude. Sure, many other actresses have done on-screen nudity; but they are usually brief, in a small environment with minimum crew. Danielle is completely nude, out in the open; and since action scenes often involve multiple takes, she was probably nude for hours at a time during the shoot.
She may not get an award for acting; but for bravado, she gets an A+ in my book.