Each episode was budgeted at $1.5 million, then the largest budget ever for a series.
The show was canceled because of high production costs and a fluctuating time-slot which caused poor ratings.
The series is replete with references to the comic books and their creators. In addition to the "Garrick Ave." reference mentioned in another item, episodes have referenced "The Hotel Infantino" (a nod to Silver Age Flash co-creator Carmine Infantino), "police captain Julius Schwartz" (a nod to Silver Age Flash co-creator Julius Schwartz), "the intersection of Gardner and Fox" (a nod to Golden Age Flash creator Gardner Fox), "Professor Zoom" (a recurring villain in the Silver Age Flash stories) and "Gorilla Grodd" (another recurring Silver Age Flash villain).
2018 in the annual Arrowverse crossover "Elseworlds", John Wesley Shipp reprised his role as the 1990s Flash (Barry Allen), so this show is canon with the Arrowverse. Also, he is said to be from Earth-90, a nod to 1990, when the show first aired.
According to producers, had the series received a second season it would have featured appearances by classic Flash villains Vandal Savage and Weather Wizard.