I'm echoing what the other comments said, the atmosphere and characters were really good but the final act felt a bit strange and... inorganic? Almost? It felt like the story narrowed a bit when we got to the heist and so it was hard to be surprised by anything since no new elements (except for that one big one).
But I enjoyed it overall and would love to see more of this setting, any story set in an underground kaiju society already has a strong hook. I think there are a lot of unique challenges that can be explored like resource/space management in a world with limited space but larger residents or accessibility compliance in a world where everyone has vastly different abilities... which admittedly sound kinda boring now that I'm typing them out but are definitely a political theme that this setting could explore. I'd love a sequel that leans more into corporate espionage.