The ending of the film regarding Kara's ceremony for her official appointment as Supergirl was handled differently from the original comics. In the film only Batman, Superman, Wonder Woman, Big Barda, and the Amazons attended the ceremony. In the comics, several of Earth's other superheroes (including Superboy, Robin, and Nightwing) made cameo appearances to also attend the ceremony. See more
In the final battle, Darkseid Omega Beams Kara into unconsciousness. As he leaves her, she's lying face-up. But when Superman sees her, she's lying face-down. See more
I know how busy you all are, but it's only appropriate that you should be the first to hear. You, who would put your lives on the line for a perfect stranger. We're all alike, for each of us, in our own way had to struggle to become who we are. But what better role for anyone to aspire to, than hero? So allow me to re-introduce you my cousin, Kara Zor-El. Or as the world will come to know her, Supergirl.
To be honest, I'm not sure I've earned the right to wear this uniform. But I will.