The music from the arcade game that young Marty plays is an 8-bit version of Max Richter's "On the Nature of Daylight". This piece of music is also heard throughout Shutter Island (2010) and Arrival (2016).
The title card symbols are: Z - arcade game, A - door with a lock, R - airplane, and K - eagle fighting a snake.
The actor that portrays a young Marty has brown eyes. Jason Bateman's eyes are blue.