I'm not entirly familier with how the comics are, but there is some brief flash backs on why he is the Punisher, diffrent though then how he lost his family in the last film. He is basically going about and killing mob bosses and anyone that gets in his way, minus killing police/FBI/etc.
Jigsaw is also in the film, dunno if anyone knows or not, as the only preview I saw was the one Wing posted here. Micro is in it too played by Wayne Knight, who I think did a great job.