I understand that I have to suspend my disbelief to watch That Batman, in fact, any comic book-based show. And I think I do a pretty good job of it. But this episode certainly tests my ability to do it.
I can buy that Poison Ivy telepathically controls the genetically altered plants. And I can believe that even a teenaged girl can don a cape and cowl and become a superhero. I'll even buy into Poison Ivy's ability to control others with her hypnotic dandruff. What the heck, I'm on board with her ability to talk to unaltered plants. But here's where I draw the line: How the hell does Poison Ivy make regular plants, plants unaltered by ChloroGene's substance, grow and move around in an instant? It just doesn't make sense. You don't see Aqua-Man making his sea creatures do supernatural things, do you? Poison Ivy should only be able to make the ChloroGene altered plants move like that. Otherwise, it would be as if all plants COULD do it, they just choose not to. Or they need a leader to prod them into doing it. It's absurd.
I also have a problem with Batgirl. Okay, I get that Barbara Gordon is an excellent gymnast, but you don't see Mary Lou Retton crime fighting or even getting into and winning a lot of fights. That's because gymnastic ability does not translate into fighting ability. In Batman: The Animated Series, Barbara had at least taken some self-defense classes. Is it too much to ask that The Batman's Barbara had something more than doing well on the uneven bars to translate into crime-fighting success? I guess it is.
On the other hand, as far as origin stories, this one is pretty good. I like that Poison Ivy is a teenager and that she and Barbara were friends. That's a nice twist. And I love what Poison Ivy was able to do with the plants (I just wish she had done with genetically engineered plants, grrrr). BTAS was never able to have Poison Ivy work on such a grand scale.
So in conclusion, if you have a superheroic ability to suspend disbelief, you should really enjoy this episode. However, if you are a mere mortal like I am, it's fairly entertaining, with big streaks of annoying running through it.