According to Dwayne McDuffie, Static was originally going to do a crossover with Teen Titans, but because of scheduling this two-part crossover episode would have aired before the first episode of Teen Titans (2003) aired. Someone at the WB network suggested the Justice League (2001) instead for the two-part crossover.
Static and Gear only encounter 5 members of the Justice League: Batman, The Flash, Green Lantern, Hawkgirl, and Martian Manhunter (no Superman or Wonder Woman). This is consistent with the original plan to crossover with Teen Titans (2003) which only had 5 members (Robin, Beast Boy, Cyborg, Starfire, and Raven).
Brainiac's voice is noticeably different compared to his other appearances in the DC Animated Universe, even though he's still portrayed by Corey Burton. Burton himself has stated that his performance was altered in post-production, presumably because the producers wanted Brainiac to sound more traditionally evil in a show with a younger target audience.
John Semper recalls really pushing for the idea that the episode teaser should really start out just like a Justice League (2001) episode, with no hint of Static Shock-he wanted it to look like the Kids' WB made a mistake and was airing the wrong show-then, at the end of the teaser, Batman says something to the effect that, 'There's only one person who can help us here.' He punches up the image on screen and we see...Static.