While the death rate from Swine flu is not higher than with the more usual types of influenza, because swine flu virus is very widespread, more people will get sick and there may be more deaths. 

The difference in the case of swine flu is that it tends to cause infection deep in the lung tissue, which is not ordinarily the case with seasonal flu.

This has been described in an interesting article describing autopsy findings in people who have died from swine flu.  This can be found at:  http://www.reuters.com/article/healthNews/idUSTRE58E6NZ20090915.  [Please paste this URL into your browser — for some reason my software wouldn’t create the automatic link]

Obesity, fatty liver disease (which often accompanies obesity), asthma, and heart disease were found in those who had died.  It is also known that children with neurological diseases and developmental delays seem more susceptible, although the reason for this is not clear.