SPOILER: Kevin Spacey's name is not included in the opening titles to keep the John Doe intrigue going. To compensate, he is listed twice in the closing credits: once before the credits start rolling and once in the rolling credits in order of appearance.
Credits roll down instead of up, contrary to common movie procedure.
The opening credits are done over broken, blurred images of John Doe removing the skin from his fingertips and sewing it into his journals.