Despite being set in The New Batman Adventures (1997) era, Batman and Robin fly in the original Batwing that was used in Batman: The Animated Series (1992). This was done because Director David Chlystek preferred the original Batwing's design.
Robin is portrayed as slightly older than he was in The New Batman Adventures (1997) and is now voiced by Eli Marienthal who takes the role over from Mathew Valencia.
This episode crosses-over with The New Batman Adventures (1997) and establishes this show as part of the DC Animated Universe (DCAU). In the comics such a crossover was not as easy since Static and the rest of the Milestone characters came from a different universe and first crossed over with Superman in a mid-90's storyline called "Worlds Collide".
At this point, neither Static nor Batman know the other's secret identity. These aren't revealed until "Hard as Nails".
Joker would again recruit metahumans in the Justice League episode "wild cards".