A powerful bug enters the world somehow and creates havoc in the US and subsequently spreads to the rest of the world. '28 Weeks Later' and before that '28 Days Later' have previously inquired into the theme of 'The Invasion'.
The similarities between the plots of the movies are uncanny. While the '28' movies had people going irrational and brainsick, the Invasion plot has people going super cool, as in unemotional. The movies are similar in this simple difference. The mobbing of the unaffected by those infected is another similarity.
This first movie, '28 days later' had a shock affect equal to those of if not more than the Texas Chain Saw massacre or Jaws in their generation. The shock was due to the sheer rawness of violence exhibited by those infected by the 'rage virus'. Tracing a group of people on the run, away from the reach of the rage virus thriving inside the victims and causing the latter to go berserk with maddening fury, the film ends with a note of hope.
'28 weeks later' improvised on the open-ended-ness of '28 days later' to evolve situations demanding difficult choices. Would you choose your own life over a dear one's (say, wife's) when in a dilemma? In this movie, the husband exposes his weak side, even as the audience empathises with him in the moment. In a storming twist to the story, there's requital for the wife. 28 weeks later is set in London and the ruined state of the imperial city is well brought out by the set designers. The acting by primarily a UK cast was impressive.
Invasion, obviously, has exploited this theme and combined threads from both the '28' movies into one, but any significant differentiation is lacking. Carol and Ben played by sylphlike Nicole Kidman and poised Daniel Craig respectively fail to show chemistry. While their acting may not be lacking, the plot fails to impress with its predictability. There is nothing new in The Invasion. The background score of 28 weeks later is haunting and permanently associative; much like how one would instantly pick up the notes of X-Files anywhere. The special effects are not great, even if there are a lot of stunts. One can see this cadre of stunts in all variation of "CSI:" and Law and Order. The effects of the bug on the skin have been better shown in the TV series X-files. There's little else to carry home from The Invasion, than a lingering sense of deja vu from 28 weeks later.
There are several loose ends left in the movie. (If you have not watched this movie and {still!} plan to, skip over to the last paragraph. The next one could divulge the plot.)
There is no mention of the deceased astronauts after the space shuttle crashes (a la Columbia). Would this happen in real world US? The epidemic does not raise its head until after a few days. Why is everyone so cool about the crash in the meantime? The virus-like organism apparently affects the genes of the infected and causes damage to the grey matter in their brains. Would such affect be reversible? There is no rational (even quasi-rational would help in a movie) explanation given about how the cure for the virus attack was found. The movie is focused on how Carol is rescued (foresee-ably). It is shown that the mass-inoculation 'drug' is showered down from helicopters. How can this be so simply achieved given that people have natural resistance need to have been affected, in the past, by a particular strain of chicken pox? Kidman is shown to have been waiting for Ben between 11 PM and 3:30 AM. This, even as Ben is supposed to be already in Baltimore. He does not arrive at the pharmacy until after the 4 hours. What was he doing, sleeping, in order to be taken over by the bug? If he could get affected, how does Carol escape the affects of the bug? She is shown have gone into sleep for a similar amount of time.
If one has watched the '28' movies, The invasion will fail to impressive in any way. One can guess there would be a sequel to this movie. I would rather spend my money and 2 hours on the third part of '28 Days Later' than the sequel of 'The Invasion', if there were to be one. 'The Invasion' can be avoided, unless you have sworn to watch every movie by the lead actors.