WraithApe’s review published on Letterboxd :
Billed as a prequel to Train To Busan from the same director, Seoul Station never really comes close to reaching the heights of its successor and lacks its emotional core, but still holds its own as a solid animated zombie apocalypse. That's something in itself I guess - I was trying to think of other zombie-based animes I've seen and couldn't really come up with anything.
It's enjoyable enough for what is, but doesn't really do anything new with the standard genre tropes; just translates them into animated form with competence. Unlike Busan, there are no hugely memorable action sequences - maybe the most unique is where Hye-Sun jumps off a building onto a kind of skeletal structure and her balance alone helps her survive, where all the semi-sentient zombies fumble and fall. It's a neat bit of physical realism. When she wakes up later on, to be greeted by her estranged boyfriend, things take a turn for the strange and the film goes in a direction I didn't see coming. 'Dream Sequence! Dream Sequence!' was flashing in my head, but it was a false alarm.
It's a damn sight bleaker than Train To Busan, but also less satisfying, and it's really only a prequel in terms of having the same writer/director team - there are no common characters or story arcs.