Well after watching this movie, I'm distinctly impressed.
The 28 franchise does what few other horror films do, and presents a highly believable piece of cinema that not only presents a very frank and unadulerated look at human nature, but features actions and plot which is extremely akin to real life.
For example.
The US leading a NATO operation in a decimated Britain. Many British fans take the attitude that as this is a British movie, the British Military should take the lead role, not the US. However, let us be realistic, regardless of whether we believe it is the best course of action or not. The US Military is ALWAYS the first to involve itself in any situation overseas that benefits them. (How does rebuilding Britain benefit the US? Who's going to run the country? A US delegated official presumably).
The frank way in which the military once again become not the salvation, but a thing to be feared is also true to case with the majority of miitaries. Sacrifice the few for the greater good!
On the subject of human nature and realism, notice, that unlike most horror movies, nobody is the heroic leader, there's no Sylvester Stalone style heroism, and the few times when a leader does emerge who is willing to take risks, they do indeed die. The “lead” male, in contrary to movie tradition, does not risk all to save his wife. He cowers and runs. A reaction many I'm sure, would realistically have when faced with such circumstances. Risk of death is one thing. Risk of infection is another.
Regarding plot, I greatly appreciated the way in which this was not merely a repeat of the first movie, which was a group of survivors in an already apocalyptic Britain. This was different. A semi-stabilised society suffering an outbreak, and with not just the “Zombies” to run from.
Finally, the ending was a bit of a shock, in contrast to the first films positive ending, the final scenes of this movie were extremely intense. No longer is Britain the sole infected area, the rest of the world is now at risk.
Overall I rate the film quite highly and look forward to the proposed sequel; 28 months later.