The narrative didn't make a lot of sense. The idea and general theme were good, but nothing was really explained. I'm also not sure if whatever it is that the main character had was addressed properly, he just felt like he ended up dragging everyone down, which I'm not a fan of when it comes to characters that deal with special circumstances.
Besides that, the actions of the humans barely made any sense. If it wad some sort of social experiment, then alright, maybe I could believe that, but they clearly had the firepower to just destroy everyone, and if that was really necessary, why not just do it? Furthermore, why put them in a city that had protection against bombs?
Also, the kid was way too old for them to act the way they did, no matter what they may have. Do these creatures count time differently?
A lot of this just feels like it happens to further the narrative and I didn't really like that. It's a -1 from me, but I wish you the best in your future works!