The storyline was well played out, as were the actors. While some have been saying things like Not having textbooks, Nor teachers, Nor a Window in a room, Nor a working heater are so impossible. Ill be graduating from a NYC Public School similar to Lincoln soon enough, and I know none of these are impossibilities. I've had classes with no teachers for days, broken heaters in classes, shattered windows in classes in the middle of the winter. And lack of textbooks, thats a constant.
Another thing-- don't discount a Police Officer in a school with a firearm. Much like was shown in this movie, this is accurately depicted, Police officers backing up SSO (School Security Officers), so Police can roam schools with firearms.
All in all, this movie makes a good call to present day students, which might not be seen the same way to adults.