I believe i know what this movie is really about
My take on the film is this: Dellamorte is in hell for killing the love of his life for whatever reason "I killed her, she wasn't dead".
This is his personal hell (Explains zombies), and that really he is with the dead for the rest of his existence. This also explains the
ending, it shows he is trapped and can't get out. I also think that the movie probably loops itself so his mind is erased and his hell starts all over
again, reliving his hell for all eternity. I got this the first time i watched, it fits perfectly.
It could also mean that he never killed her, but got executed because the jury found him guilty for the crime anyway (Explains his sidekick "killing" her) and
he got put in hell anyway.