What is one of the ways that video games of the 1960s were different from video games of later decades?

Video games of the 1960s were entirely electronic, while many modern videos games have a mechanical component.

The only major difference between video games of the 1960s and modern video games is the quality of the graphics.

Video games of the 1960s were completely mechanical, while modern video games are all partially mechanical and partially electronic.

Many video games of the 1960s were partly mechanical, while modern video games are completely electronic.