The official Twitter page of the First Squad, has some interesting information. Apparently the film was originally planned to be a 13 episode OVA with larger story arc, but eventually it was decided to make it a movie. The creators are not letting their offspring go away so easy, so they are planning three more sequels, while the script for the second film is already completed and the production will begin this winter. The sequel will be in horror genre, at least they will try to make it a horror. I am not sure what they mean by that, but it sounds exciting.