I've posted nice looking trailer before, and now I have two intense scenes from the Mutants (2009). Just over one minute long each, but it's enough to get the powerful sense of the fear coming from it. This is the sign of a good movie.
In a world devastated by a pandemic virus that turns human beings into primitive and bloodthirsty creatures, Marco and Sonia set off to find a secret base to escape from the 'mutants'. When the latter attack them, Marco is infected too. Little by little, he undergoes the same changes. Sonia, who is expecting a baby, is then forced to fight her worst enemy, the man she loves.