Proof that many evil sorceresses don't know astrophysics - Morgan's visions of Mars show a sun that is the same size as it is on Earth - too big for Mars.
Does the Flash really not understand what a "whirlwind" is?
They said in part one that the Philosopher's Stone was from the hilt of the sword Excalibur and thereby the source of its power. But the stone is shown to be a cubical piece or rock that by no stretch of the imagination could ever fit into the hilt of a sword!
Throughout scenes when J'onn comes to Morgaine from the Javelin 7, Mordred's hat keeps changing from yellow to purple.
When Flash seals the Philosopher's Stone in the vault he uses a device that reads his palm print. But the problem is that he still had his costume's glove on at the time, so how could it have read his palm?
Why did Etrigan tell Flash to make a whirlwind? Everyone could have just punched out the frozen warriors.
Why didn't they just destroy the Stone in the first place, instead of locking it up on the Satellite?
So how did the League get to London? One second they say they're stranded (because J'onn stole the Javelin 7), then Batman says he's got another way off, and then they pop up in London. It looks like the Demon teleports them, but this is never made clear.
Wonder Woman: I don't like the way he looks at me. It's like he sees into my very soul.
Mordred: Get out of my castle! (fires magical bolts)
Flash: Whoa, the kid's got chops too!
Wonder Woman: The rotten apple doesn't fall far from the tree.
Flash: (picking an ice needle out of his rear) Well, that was a pain in the butt.
Flash: (to J'onn) Who knew? Underneath that goofy green skin, you're human after all.
Batman: We'll do whatever it takes.
Demon: Are you prepared to take out one of your own?
Batman: I said, whatever it takes.
Demon: You stupid, ignorant, pathetic excuses for heroes.
Wonder Woman: It can't be.
Demon: Oh really, your Highness? Take another look!
Demon: Flash, we need a maelstrom?
Demon: A whirlwind. (Flash looks blank) Run real fast!
Flash: Go find some other house to haunt.
Wonder Woman: He didn't mean that.
Demon: Do you think I care?
Flash: I'd like to see her get (the Stone).
Demon: Be careful what you wish for, little man.
Flash: (trying to impress some women) Superman? Yeah, he's a close personal friend.
Flash: Ding. Fifth floor, sporting goods, hardware, evil sorceresses.
In the party scene one of the party goers dressed in a Batman costume is doing the Bat-Tutsi--the dance made famous in the 1960's television series Batman starring Adam West as the Caped Crusader.
Superman, Hawkgirl and Green Lantern do not appear in this episode
Batman: Whatever it takes.
For those that have been keeping up with the Batman/Superman WB continuity, Batman has said this on at least three separate occasions. The first time was in Batman: Mask of the Phantasm. He has also said it in the Batman Beyond episode "The Call." And now in this episode of Justice League.
You can see Kirby's creation Vykin the Black (of the Forever People) at the party again, as well as one of the faceless agents from Jack Kirby's OMAC series. Harley Quinn and several other lesser characters are there as well. The worm that Harv is transformed into is "The Eater" from Kamandi #18. The guy with the buckethead is Devilance the Pursuer, a badguy from the Forever People comic.
Flash: Hey, Cecil, over here!
A reference to Beany and Cecil, a 60's-70's cartoon series about a boy and his sea serpent.