We're Back! A Dinosaur's Story/WMG

Captain Neweyes is evil.

 * Neweyes doesn't see any problem with travelling back in time, capturing dinosaurs, force-feeding them chemically treated cereal that drastically alters their behavior, shoving them out of his airship into the New York harbor, and . He's apparently made quite a killing for himself feeding this same cereal to children in the future. So, Beware the Nice Ones indeed.
 * Not to mention letting clumsy giants stumble around a crowded city.

Neweyes caused the hat to fall on the little girl's head.

 * Hardly an impressive theory, but he is a wish-granter, and the girl appeared once over the wish radio, so he probably did it.

Professor Screweyes didn't die because he wasn't alive to begin with./This is the same universe as The Crow.

 * People assume the crows eat him at the end but that would make them feathery super-piranha and not birds with as fast and completely he disappears. One minute he's there, the next a flock of crows lands on him and do not move an inch until they fly away only a few seconds later leaving nothing but the screw, meaning they would've had to have eaten flesh, clothing, gristle, and bone. The only way the scene really makes sense is if you assume that Screweyes was really a vengeful ghost in the same universe that The Crow takes place in. This explains the powers he has (the only special effects in the circus shown to be tricks are the ones involving people in costumes but not the animated smoke, illusions and certainly not the hypnotism, nevermind the whole contracts signed with blood thing) and also why his biggest fear is the crows. They're the only ones who can, if he loses control over them, take him back to the land of the dead which is what seems to actually happen.

Neweyes and Screweyes are actually an angel and a demon, respectively.

 * Neweyes can travel through time; lives in a golden flying craft filled with light that apparently hangs about above the earth most of the time; bestows intelligence and goodness on animals; and not only listens to wishes (read: prayers) but works to answer them without using direct influence as much as possible. He also offers to save his "fallen" brother but doesn't force the issue, only making the offer and then ascending into the light shaking his head with pity when the offer is refused.
 * Screweyes is earthbound, living in a dark underworld-like house of horrors; uses fear, illusion, and drugs (read: potions) to turn people (and animals) toward their 'primal natures'; and employs tricks and lies to coerce otherwise good people to sign eternally binding contracts in blood. The most telling thing is that Screweyes used to be a good guy until a crow pecked out his eye, making him "crazy," and now he surrounds himself with the very things that destroyed him with no way to escape on his own, seeming to only be evil out of contempt and spite towards his "brother."

Neweyes already solved all the worlds' problems.
After using his Brain Grain to make everyone in the galaxy smart and creating galactic peace through an intellectual revolution, Neweyes realized that the future now rather dull with no war or conflict of sorts. So he decided to use his time-travel technology to dick around in the past.
 * This last part is more likely in the case of Screweyes. He was the one who traveled into the past and started a circus of fear with his fear radio and his braindrain pills, all future technologies.

Both Neweyes and Screweyes come from the future.
While this is implied in the movie (how close could Neweyes have a brother living in the 1990s, which is presumably decades, if not centuries in the past of whatever era Neweyes came from?), the future isn't pleasant. After all, it produces individuals like Screweyes and gives them access to time travel to terrify people in the past.