So I was really excited for this, as a big fan of both Hellbound and Train to Busan. (Which was incredible).
Unfortunately, it just doesn't hold up to the level of either of those.
There was a lot of really interesting ideas there, they just weren't explored as much as they could've been, which would've been better served as a television show, or miniseries, which would've allowed them to flesh out the characters and concepts more. Set pieces were beautiful, the acting was good, and it felt like the director and writers had something interesting to say, but due to its runtime, they just didn't get the chance to explore any of it to the amount it deserved. When it finished, I actually double checked it was actually a movie, and not, in fact, a double iength pilot episode. Unfortunately, this means there's some big problems with pacing.
I also finished the movie thinking "that's it?" due to the aforementioned not followed up on ideas.