Peter Ericson’s review published on Letterboxd :
An engaging story with a thought-provoking subtext of xenophobia and apartheid, generally excellent special effects, and original and impressive filmmaking characterize "District 9", the feature-film directorial debut of Neill Blomkamp, who also co-wrote the screenplay with Terri Tatchell. At the same time, however, it is difficult to fully connect with the material, and the film never realizes its full potential.
After a slow start, the movie becomes increasingly intense as it unspools, with some explosive action sequences. The last half-hour or so is positively pulse-pounding, while also featuring a few quieter moments of what can best be described as awe in the scenes involving the giant spaceship.
Gritty, documentary-like cinematography and an atmospheric score. "District 9" gains poignancy and an extra dimension by being set in Johannesburg, South Africa.
While a sequel is certainly possible, given the open and rather abrupt ending, it is neither really needed nor necessarily desirable. The ending provides a sense of closure and manages to be satisfying without answering all the questions that the movie raises.
Working in the film’s favor, the lack of well-known actors helps to create an aura of authenticity. Sharlto Copley is outstanding as Wikus Van De Merwe, the central character.