New 'Superman' Extended Trailer Released, More Krypto the Superdog

A new trailer for "Superman" has dropped ... and, it's giving fans a longer look at Krypto the Superdog -- and, a peek inside the Fortress of Solitude.

The new clip -- which runs about five minutes long -- came out Thursday, and while it features much of the same footage from the trailer that was dropped in December, it's got a whole lot of new content too.

Check out the clip ... the first three and a half minutes features an extended look at the original trailer's opening scene where Superman, played by David Corenswet, calls on his dog Krypto to save him.

Instead of just licking his face and pulling him to safety like he does in the original trailer, Krypto's looking to play with his owner -- jumping all over his body, biting his arms and acting like the typical big dog that doesn't know its own strength.

Eventually, Krypto drags him to the Fortress of Solitude ... where a group of helpful robots detail his extensive injuries -- 14 broken bones and damage to his internal organs -- before using radiation from the sun to patch him up. Looks like Supes is hurting pretty bad from the treatment though.

The rest of the trailer appears to be scenes from the original ... again showing fans Nicholas Hoult's Lex Luthor and Nathan Fillion's Guy Gardner.

Warner Bros is making a major marketing push with this trailer BTW ... 'cause it's supposed to play before every screening of "A Minecraft Movie."