Justice League: Gods and Monsters is a dark take on the heroes we thought we knew — you can read our interview with project lead Bruce Timm in another article if you're curious about the project — and this new excerpt from the release shows a Superman that's willing to kill.
It's an interesting decision, especially since Superman killing General Zod at the end of Man of Steel was such a controversial decision for fans of the character. This version of Superman is actual General Zod's son, complete with facial hair, and the death at the end of the short is more or less consensual.
This matches up with the other excerpt we ran on Monday; this is a dark world where your heroes kill people.
Testing the moral and ethical boundaries of superheroes is always an interesting thought exercise, and this shows how well it can be done.