'Ere are some new hints!
#30: Wearing certain clothes that could be obtained via the social club triggered a bug that erased every mission's first cutscene.
#29: This game featured a foe who would often get in the way of the protagonists, and thinks highly of itself. He's also a recurring foe in sequels and prequels, and made his last appearance as both a donwloadable content and a patch on the latest entries.
#28: Marco! Polo...?