Batman v Superman: Dawn of Justice isn’t just a superhero movie, it’s an event. Zack Snyder’s blockbuster not only features two pop culture icons clobbering the crap out of each other, the plan is for the film to kick down the door to the rest of DC’s cinematic universe.

As the opening act to 2017’s Justice League — Part 1, what are some things sharp-eyed viewers should look for in Dawn of Justice? A few things.

1) Anything with Darkseid, or his Omega symbol.

Darkseid is the biggest, baddest dude in the DC Universe and could very well be the villain in Zack Snyder’s Justice League movies. Some early photos of Dawn of Justice reveal that Darkseid has a small, but significant role, even if he may not show up at all.

Keep an eye out for the Omega symbol. The “Knightmare” sequence — the weird dream stuff where Batman fights Superman in the desert — is likely where Darkseid will make himself most known.

The Omega Symbol in 'Dawn of Justice.'

2) Jason Mamoa’s cameo as Aquaman.

One of the earliest official looks at Dawn of Justice was Game of Thrones alum Jason Mamoa as the Atlantean superhero, Aquaman. But since then, Aquaman has been left off all the trailers and TV spots, indicating his appearance will be incredibly minor. But he’s gotta be in it, right?

Early plot rumors involved Mamoa’s Aquaman seen briefly as Lex Luthor’s prisoner. But those claims have sounded less likely over time. Still, Aquaman’s gotta be in there somewhere?

3) The identity of Robin.

Batman is well into his superhero career by the time we meet him in Dawn of Justice, but it’s unclear how many different people — if any — have taken up the mantle of his Boy Wonder.

Here’s a quick comic-book lesson: Several in Batman history have assumed Robin’s identity. First was Dick Grayson, arguably the most widely known Robin, who grows up to become Nightwing. After Grayson, the next Robin was Jason Todd, a violent kid with a mean streak killed by the Joker in Jim Starlin’s 1988 comic arc A Death in the Family. After Todd came Timothy Drake, then briefly Stephanie Brown, and lastly, Damian Wayne, the son of Bruce and Tahlia Al-Ghul.

Robin's costume hangs in the Batcave in 'Dawn of Justice' -- but who was Robin?

In 2013, Girls and The Force Awakens star Adam Driver was rumored to play Nightwing, but these whispers have all but disappeared. Judging from the preview images of a Robin suit defaced by Joker graffiti, comic fans and betting types should put money on Jason Todd. (Disclaimer: I’m not responsible if you lose).

4) Ezra Miller’s cameo as The Flash.

Another DC superhero making an appearance in Dawn of Justice is The Flash, played by Ezra Miller, not TV’s Grant Gustin. According to Zack Snyder in an Entertainment Weekly article, Barry Allen will deliver “a cryptic message” to Batman in a dream sequence alongside some of the Darkseid stuff in the movie. But is it a dream, or is it something else? (Spoilers: It’s totally not a dream. Justice League is happening, remember?)

5) Another villain that isn’t Doomsday.

When the second trailer for Dawn of Justice premiered on Jimmy Kimmel Live! some fans were concerned it spoiled too much (though, aren’t we always looking for details?). It was the first time anyone saw Doomsday, the notorious monster from 1992’s The Death of Superman that “ended” Superman (although you should know death takes in comics).

In The Daily Beast, Snyder played coy and hinted that there’s more to Doomsday, and to Dawn of Justice, than we all think:

In a weird way, Justice League is the next step for these characters to form a bigger team,” he teased. “Maybe there’s a bigger enemy to fight.”

Did he mean Darkseid? Brainiac? Ever ambiguous, Snyder hinted at what he may or may not have planned for the Justice League’s “bigger enemy.” “Well, you have Doomsday, right? He doesn’t just crawl out of the ground. He has his own mythology, right? So that has to be explored…”

The tight-lipped Snyder’s not giving up much more than that for now. But he does want audiences to begin thinking about DC’s superhero brand in macro terms. “To us it really made sense to give [Doomsday] to the audience now. I really wanted to make the audience a promise that… though I’m super excited and happy and fulfilled by the conflict of Batman and Superman, there’s also a bigger world to start to think about.”

Batman v Superman: Dawn of Justice releases in theaters worldwide on March 25.