In the original script for Genesis, Hiro was to exclaim "Bonsai!" after discovering his powers. According to a statement by Masi Oka on The View (1997), he approached Tim Kring and informed him that "bonsai actually means 'little tree'", and that he probably intended banzai. Because Masi felt that banzai had wartime/old-fashioned connotations, he asked if it would be okay to use the more modern exclamation "Yatta!" instead. Tim Kring gave Masi permission to change the line by replying along the lines of, "Dude, go to town."
In the originally aired version of the pilot, Claire injured her hand badly by putting it into a running sink garbage disposal to retrieve her class ring. However, Emerson (the company which makes the "In Sink Erator" brand disposal which was used in the shot), threatened to sue NBC for airing footage which they claimed "seriously damaged the reputation" of their product. NBC settled out of court, so all future airings of this episode have the "In Sink Erator" brand name removed from the offending shot.
When Hiro and Ando walk into the bar to have a drink, two guys are singing karaoke on the stage to the Backstreet Boy's "I Want It That Way". This is a reference to a popular YouTube video that features the Back Dorm Boys, two Asian men doing a spoof performance of the same song. The men in the bar in Heroes are dressed in the same orange basketball jerseys, and one has a white sweatband around his head.
In the original version of the pilot, when Simone and Peter arrive at Isaac's loft, they find that he has cut off his own hand. These scenes were used in some of the promotional videos for the series, but the script was later changed to say that Isaac had only overdosed.