20 Things You Somehow Missed In Back To The Future Part 2
14. Marty Jr. & Griff Have Different Eye Colours To Marty Sr. & Biff
A lot of the movie's fun lies in seeing the various different versions of its central characters across time and also their descendants, particularly Marty's son Marty Jr. and Biff's grandson Griff.
Though Marty Jr. and Griff have obviously been given different clothes and hairstyles to distinguish them from their ancestors, Robert Zemeckis also opted for an altogether subtler visual flourish to earmark the younger characters, and one you probably didn't notice.
Marty Jr. and Griff both have brown-coloured eyes while Marty Sr. and Biff's eyes are both blue. It's a clever piece of visual shorthand to help sell the difference to the audience, and even if you didn't consciously notice it, there's a good chance your brain still did on some level.