Let the opening sequence run four times without doing anything, and you should have a new opening sequence in the movie options
Once Vincent is unlocked, it is possible to view an extra image of him. At the character select screen, highlight a character before or after Vincent. Press Up and, depending on Vincent's position in the Character Select screen, press the Up-Left direction if you're on the right, or Up-Right direction if you're on the left. Vincent will be highlighted as a Turk.
There are two extra opponents in Arcade Mode, Cloud Strife and Tifa Lockhart. You can fight them by defeating everyone up to Sasuke in under 3 minutes and 20 seconds.