The phrase, "Always leave them wanting more" usually makes sense, but the new District 9 has so many unanswered questions that it suffers.
About a third of the movie is eaten up by a wearying action sequence that would have been better spent adding some back story to the aliens or more of the political intrigue of how they were able to be contained in a Johannesburg, South Africa slum, for instance.
As it is, District 9 has a few creative elements but relies far too frequently on old tricks from movies like E.T., Transformers, Terminator, Planet of the Apes, and 28 Weeks Later. The acting if very good, the documentary elements hint at telling a great story, and the social commentary touches on how barbaric uneducated humans often are and how business usually trumps government, but the herky-jerky motion of much of the camera work makes this film tiring to watch.
And the many plot holes feel sloppy. This could have been such a great movie. But then again, one would hope the producers (including Peter Jackson of Lord of the Rings fame) are smart enough that they're simply leaving room for what could easily be a money-making ream of sequels and prequels.
Filling in the plot by making this a movie series might someday land District 9 a higher ranking than:
*** out of ***** stars