The design of the bad guy, Evil Otto, is based on the smiley face made popular in the 1960's. The developer, Alan McNeil, despised the image, because he felt it depicted a kind of "fake friendliness" he associated with businesses and salesmen. He made Evil Otto into a Smiley just to add a little sarcasm to the game, imagining the tagline "Have a Nice Day!", which frequently accompanied the smiley face, as here meaning "Have a Nice Day while I beat you to death."

Evil Otto's name, however, comes from the security manager at Alan McNeil's previous employer, Dave Nutting Associates: Dave Otto. Nobody at DNA liked Dave Otto, because he instituted strange and annoying policies, which Alan collectively described as "you are all guilty until proven innocent".
Contributed by gamemaster1991
In January 1981, 19-year-old Jeff Dailey died of a heart attack not long after posting his high score of 16,660. The same thing happened in October of the following year, when 18-year-old Peter Burkowski died seconds after getting the high score twice in a matter of only 15 minutes. Both victims were known to be healthy, and the heart attacks were thought to be caused by stress.
Contributed by gamemaster1991