Disclaimer: Knowing full well there is a wealth of resources available to fans of the "Justice League" animated series, I have no intention of doing a bunch of dry story synopsis with the occasional new screen grab. I will chronicle, within reason, J'Onn J'Onzz's specific journey over the course of the series, but chiefly I will be reviewing the episodes through my own jaundiced perceptions.
Michael Rosenbaum works perfectly fine for me as the Wally West Flash, specifically from the Mike Baron/Bill Loebs/JLE era. I could see where fans of Barry Allen or the Waid/Johns Flash might take issue, but the team needed an over-enthusiastic wise guy youth in its dynamic. Screenwriters Fogel, Dini, and McDuffie wisely play him off the hardened veteran Green Lantern John Stewart. The dynamic is curiously unique to the screen, as the classic Barry/Hal team was one of equals, or in retroactive continuity, with Barry as the salt of the Earth to Hal's somewhat flighty hotshot. Wally and Hal never seemed to relate much to one another, while West played the critical skeptic to Kyle Rayner's well-intentioned if stubborn rookie.
This specific story is exceptionally well cast, with former failed live action Martian Manhunter David Ogden Stiers better serving as the super-intelligent gorilla Solivar, demoted by story necessity from king to security agent. Virginia Madsen plays a chilly scientist under the sway of Powers Boothe's Gorilla Grodd. The latter perhaps recalls the 70's Super Friends classic Solomon Grundy a tad too much with his pronounced drawl, but it's all in good fun, and sings to the ear. Bill Duke also turns up, sadly to lesser effect.
When Green Lantern questions Flash's story about having been framed for a crime he did not commit by a talking gorilla, he retorts, "Hey, we both got a Martian's phone number on our speed dial. I think I deserve the benefit of the doubt here."
Later, after the Flash's impetuousness leads to Central City being wiped off the map, J'Onn J'Onzz, Wonder Woman, and Hawkgirl investigate. J'Onzz co-piloted a Javelin that scraped against the side of an invisible forcefield that encircled the city's former location. Unable to penetrate the field, the trio contacted Batman, whose analysis yielded an energy signature in the area identical to one found in Africa. The intercontinental quartet had found Gorilla City, shrouded in illusion, and Gorilla City now had them. Knocked unconscious by energy weapons, our heroes were taken prisoners as spies and faced brutal interrogation. When J'Onn J'Onzz tried to protest, he was laid low by an energy charge in his restraints. J'Onzz continued to be beaten and questioned by a Gorilla General, wonderfully voiced by Phil Morris. The actor who would later play MM foe Vandal Savage on the series, friend King Faraday in the animated "New Frontier," and J'Onn J'Onzz himself on the live action "Smallville."
Batman picked his lock and effected the release of his teammates, quite thanklessly, as they fled the scene by air while he ran through the city streets. At least J'Onzz saved some face by being the only flier who remembered the forcefield, rather than slam head first into it like the ladies, whom he gently set down. The machinations of Grodd then caught up to Gorilla City, allowing the Leaguers a bargaining tool for their freedom. Grodd had launched a series of missiles at his home town, though all of them were dismantled by the League, one by J'Onn J'Onzz. Wonder Woman seemingly perished in a similar attempt, prompting Batman to try digging her out from under a disarmed missile that had been embedded in pavement with his bare hands. J'Onzz rested his hand on the Dark Knight's shoulder to halt his hopeless endeavor. Almost immediately, Diana turned up alive and freed herself. What is it with J'Onn prematurely heralding the demise of his fellows? Grodd meanwhile was outsmarted by the Flash and temporarily left a vegetable.