The early stages may be a bit rough going for some people, as most of the heroes start off, unsympathetically, mugging a young nurse who also lives on the block. But alien invasions have a way of changing people. Or so I've learned from the movies. The protagonists all live in Wyndham Block -- I don't know whether this is a real housing project or an homage to British science-fiction great John Wyndham or both.
There are clever elements of other classic British alien-invasion movies and novels to note along the way, while the climax reminds me (in a good way) of the denouement of a lot of Dr. Who episodes. John Boyega is charismatic as the leader of the youth gang who learns better through adversity, Jodie Whitaker is suitably spunky as the nurse, and Simon Pegg's perennial on-screen and off-screen collaborator Nick Frost shows up to lighten things up as the flunky of a drug dealer. Recommended.