The train carrying the Euros to Kasnia is heavily guarded, yet the train is traveling with the armed guards standing inside open doors. Wouldn't it be more secure for the shipment to be guarded inside freight cars that have the doors closed and locked?
Green Lantern says, "It sounds like Wally...but how can we be sure?" after Dr. Fate switches the Flash and Luthor back to their proper bodies. If Green Lantern is unsure as to whether the exchange worked, then why did he use Wally's real name and possibly compromise the Flash's secret identity?
Trivia: The coordinates gives for Kasnia are 45°9'8''N, 19°58'13'': somewhere in northen Serbia and Montenegro. (However, there is no mention whether this is Kasnia or just on-route to Kasnia.)
Trivia: Flash once more identifies himself with membership ID 006.
No matter who they think Lex is, at the end why didn't they restrain his hands? He's just "strapped" into a chair with a band across his upper arms.
When Mr. Terrific cuts the gravity, we see Lex-in-Flash hit the deck extremely hard. And a crate next to Terrific drops down. But there's no sign or sound of all the other stuff in the air (including several Watchtower crew) dropping.
When Lex starts his mind probe on Grodd, Rampage is nowhere to be seen. But after the commercial break Rampage shows up out of nowhere to say "Psycho."
Why would Polaris be asking Luthor if he was going to wash his hands in the restroom if he was wearing gloves?
Tala: Lex? Is that really you?
Lex: Of course it's me, you twit.
Tala: (disappointed) Oh.
Green Lantern: It sounds like Wally. But is there any way to be sure.
Flash: You want proof? Until he went off into the Marines, GL's nickname was…
Green Lantern: Stop! It's him. You promised never to repeat that story.
Flash: I know – I was just messing with your head.
Tala: Dr. Polaris is this far from open revolt. He's treacherous. I want to punish him, baby, sooo verrry badly.
Flash-in-Lex: Right, sure. Just one question - do I know you?
Grodd: It must pain you to see me like this after what we've been to each other.
Tala: My taste in boyfriends has evolved.
Dr. Polaris: (to Luthor) We don't think you've got what it takes to run the show. You've been acting unbalanced. Holed up in that lab, talking to yourself.
Sinestro: After Grodd tried to turn the world into apes, you can imagine how seriously we'd take something like that. What are you going to do, make everybody bald?
Tala: Lex…don't talk to the rock.
Flash: What do you say we go check with Batman? He's got clues.
Tala: Rest in here, darling
(Tala and Flash-in-Lex go to Lex's room, close door)
Flash-in-Lex: Hey. That's not restful.
Flash-in-Lex: Okay, okay: I'm trapped in a building full of supervillains, I've lost my powers, and for some reason this creepy hot chick thinks I'm...- (sees himself in the mirror) ...Lex Luthor! Oh, that is just wrong. Cripes.
Flash: Man, just be careful with my head. It's where I keep all my one-liners.
Flash-in-Lex: (to the Legion) My fellow bad guys - I, Lex Luthor, your leader, will speak now about my, Lex Luthor's, plan. My villainous, villainous plan. Question the plan at your peril!......Uh, any questions?
Bizarro: Me got answer.
Flash-in-Lex: Excellent. Do enlighten us.
Bizarro: Ever since you plug into monkey's head you act perfectly sane and rational. Am you Bizarro mommy?
Flash-in-Lex: Me, The Flash? You've, like, totally lost it, Grodd - I'm Lex Luthor!
Grodd: And I'm Charlton Heston.
Grodd: Ah, Tala, my old groupie. I so miss bending you to my will.
Tala: Go eat a banana. Lex is my man now.
Luthor-in-Flash: If nothing else, I can at least learn the Flash's secret identity. (unmasks) I have no idea who this is.
Dr. Polaris: You gonna wash your hands?
Flash-in-Lex: No, 'cuz I'm evil!
The voice of Red Tornado was played by Powers Boothe. Bruce Timm notes that he had to make the voice a higher pitched "robotic" tone to mask Powers' deep, familiar voice.
This episode first aired on YTV in Canada on March 29, 2006.
Michael Rosenbaum also plays Lex Luthor on Smallville, meaning in this episode he's essentially playing the same role in both a live show and an animated show.
Other villains who appear without dialogue: Giganta, Black Mass, Queen Bee, Neutron, Livewire, Dr. Destiny, Atomic Skull, Silver Banshee, Rampage, the Key, Toyman, The Dummy, Lady Lunar, Merlyn, Fastball, the Gentleman Ghost, the Top, the Shark, KGBeast, Weather Wizard, Dr. Spectro, Evil Star, Sonar, The Thinker, Sportsmaster, Monocle, Tattoed Man, Crowbar, Electrocutioner, Bloodsport, Psycho Pirate, Parasite, Javelin, Cheetah, Copperhead, and Heatwave.
Other heroes who appear without dialogue: Stargirl, Starman, Wildcat, Elongated Man, Captain Atom, Booster Gold, and Ice.
Clips at the end are from "Grudge Match" and "Far From Home."
Michael Beach, Clancy Brown, Juliet Landau, Powers Booth, Ted Levine, Lauren Tom, and George Newbern reprise their roles as Mr. Terrific, Lex Luthor, Tala, Gorilla Grodd, Sinestro, Dr. Light, and Bizarro. The actors voicing Red Tornado, Rampage, Angle-Man, and a Legion guard, are uncredited. Due to producers avoiding crediting the same actor for multiple roles, Phil LaMarr and MIchael Rosenbaum are uncredited for playing Steel and Dr. Polaris, respectively. George Newbern is on-screen credited as Bizarro for the first time since he appears here when Superman does not.
This episode was aired on Toonami UK on January 25, 2006.
The Cosmic Treadmill
When Doctor Fate enters Wally's mind, you see flashes on Wally's past or people encountered. If you look at the upper-right hand corner, you see the Flash running on what appears to be a treadmill. This could be a homage to the Cosmic Treadmill, which was a time-traveling/dimension-jumping treadmill invented by Barry Allen, the second Flash.
Lex-in-Flash: Beam me out of here...
This is a reference to the show Star Trek where the characters are beamed out of their ship. A famous line being, "Beam me up/down, Scotty."
Grodd: And I'm Charlton Heston
Grodd makes a remark about the actor Charlton Heston, who starred in the movie, Planet of the Apes and its sequel.
The Great Train Robbery is the name of the famous early Western film made by Edwin S. Porter in 1903. Only about ten minutes long, it was the first narrative film. The Great Train Robbery is also the name of a 1975 novel and 1979 film by Michael Crichton.