It's getting hard to support the theory that Zack Snyder made a thoughtless mess with Batman v Superman, since so many quality Easter eggs seem to keep getting unearthed. The latest discovery confirmed by director Zack Sndyer goes back to that crucial "Knightmare" sequence from the film, and an all-important detail that just about everybody missed:
Remember when Judas said Joker was referenced in BvS
And y’all all laughed
As I laughed
As we laughed
Zack gave me the last laughApril 16, 2018
This endorsement by Zack Snyder seems to clinch things: Jared Leto's Joker played a bigger part in Sndyer's version of the DC Extended Universe mythos than most fans ever realized - the sole exception being critical-minded viewers like Judas, who put the puzzle together - even in the face of overwhelming fan skepticism. The level of detail (the symbolism of Superman burning out Batman's heart in the Knightmare scene) continues to showcase just how deep Snyder's reverence for these characters really is - much more so than he typically gets credit for.
If you don't get the reference: DC's 2013 hit video game Injustice: Gods Among Us saw a alternate universe storyline where The Joker kills a pregnant Lois Lane and destroys Metropolis through vile means of manipulating Superman. That act drives Superman to first kill Joker, leading to a falling out with Batman, as Superman grows into a ruthless dictator ruling through a fascistic idea of order and justice. The remaining DC heroes form an insurgency to resist, and bring heroes from an alternate timeline over to their world to help save them. The game then details that fight for freedom.
From the reference above, we now have to wonder just how much of Injustice Sndyer planned to inject into the future of the DCEU saga. The connection helps makes sense of what we saw in the Knightmare sequence - especially the appearance of Ezra Miller's Flash from an alternate future. Fans assumed that scene would be connected to the Justice League's fight against Steppenwolf, but it could have been from something much bigger, and later, in the DCEU saga. Snyder himself confirmed a connection between Superman's tragic turn and the Anti-Life Equation that Darkseid has been known to use, so it seems there was indeed a larger story taking shape in Snyder's mind.
Since the future of the DC Films franchise is so unclear at this point, there's no telling if any of this is still relevant, or just more of the 'would've, should've been' that goes hand-in-hand with the story of Snyder's time as the DCEU architect.
Justice League is now on home video. The DCEU continues with Aquaman on December 21, Shazam on April 5, 2019, Wonder Woman 2 on November 1, 2019, Cyborg in 2020, and Green Lantern Corps in 2020.