Even though the story is disconnected from the show I think you should watch it first to get aquatinted with the characters and mode of storytelling because it definitely isn't for everyone. the basic premise is that an anthropomorphic rat named Gregory the other various non-human tenants torment the main character until they get their life in order. this is a surreal horror comedy using admittedly rather hamfisted metaphors to explore how the main character is running away from their problems. it gets borderline incomprehensible at points but not in an annoying way. this takes some creative liberties with the character's roles and personalitiesbut not so much that it's distracting. I also like the fun visuals in the building itself, the original show was on a shoestring CGI budget so they couldn't do that.
I must say that this story feels like it moves too quickly. the original isn't exactly long either but it has this slow creeping ambiance about it that kinda got lost in translation, especially with all of the colorful characters they have to introduce in such a short amount of time. Oh but believe me, they're memorable.

overall a fun extension for fans of show but wont change your mind if you already don't like it.