The story is simple. A group of people living on the top floor of a soon to be demolished tower block wake up one day besieged by a sniper. They don't know who what when why or how, but someone is relentlessly shooting their asses off, and they - for the most part - would prefer their asses remain in their general ass area.
It's pretty classic stuff. And once we get rolling, Tower Block embellishes it with a group of characters who manage to rise above their stock natures. There's the final girl, but she's a bit more aggressive than usual. There's the nice old man, but this time he's also sort of a badass. The mother with little kids is a total bitch, while the young male hero is a detoxing alcoholic (rather than turn this character trait into a time wasting attempt at pathos, the film smartly just gets him drunk, and it's awesome).
But the big scene stealer is Curtis (played by Jack O'Connell). The besieged floor houses three hoodlums who charge the rest of the inhabitants protection money. While two remain mostly bland thugs, their leader, Curtis, goes from obnoxious villain to audience favorite pretty quickly once the bullets start flying (after, actually, since he sleeps through the initial attack). A small, young white kid with a big mouth, Curtis reprents the genre's selfish bastard trope yet somehow manages to simultaneously provide both the comic relief and biggest moments of badassary. He's amazing and totally worth seeing the film for.
With a set up like this, audiences will have to be in a mood to forgive script conveniences, and some will find that harder than others. This is one super sniper, able to cover a bunch of windows with lightening speed and super precision. The sniper's identity is eyeball worthy as well. Most damning, the victims inside the tower are basically safe so long as they sit in their hallway and don't move. Nearly every death in the film following the first attack requires a bit of contrivance.
But that kind of stuff happens all the time genre films, especially slashers. And as much as this is a siege film, it's also fits the slasher mold, albiet with guns instead of knives and chainsaws. It's a refreshing take. The kills are definitely set up with the samel
The film does attempt some bigger picture social commentary stuff regarding urban decay. Tower Block joins ranks with Attack the Block and Harry Brown as films about how awful these British project buildings are, and they truly do look bad. The film's victims are not only isolated by being the last occupied floor in the building (a text information dump and a brief opening explains how that's possible) but by the large swaths of empty, nearly apocalyptic concret jungle surrounding them in every direction.
But that stuff isn't explored to any real extent and fails to supply the film with any additional emotion. It doesn't occupy much running time either, so it's kind of a wash. At its core, Tower Block remains a lean, funny, occasionally brutal, crowd pleasing thriller that totally accomplishes its goals, minor as they are. If it sounds up your alley, then it's probably up your alley.