I have long said that Nazis are the perfect movie villain (or real-life villain) because they are universally evil. Zombies are one of the perfect movie monsters: They are gross, they are violent, and (with a few minor exceptions that don't really count in my book), zombies don't speak, so there is no worry of them charming you to their side.
So you mix zombies and Nazis and you have the perfect cinematic villain. This is what makes Dead Snow such a successful movie franchise. It's a movie about Nazis that are resurrected into zombies. What more do you need to know to enjoy the film? Nothing, really, but more knowledge doesn't hurt:
Expect to see zombie Hitler in Dead Snow 3.
EW recently spoke to Tommy Wirkola, the writer/director of Dead Snow and Dead Snow 2: Red vs. Dead, who promised a third Dead Snow would be made, at some point:
“We’ve got to finish the trilogy, so I’m very excited about that. We’ve got to finish what we started, all of us! We have some ideas. I think it’s natural to maybe put some of the story in South America, where a lot of the Nazis fled, of course. We’ve got to top what we’ve done before, we have to bring back Hitler as well. Zombie-Hitler. That just feels natural.”
The Norwegian filmmaker warns that it will probably be "a few years" before Dead Snow 3 is made. According to his IMDb page, Wirkola is in development on an action film called War Pigs and a sci-fi comedy called Afterburn.
If you are looking for more Nazi zombie fun, Dead Snow wasn't the first to tackle this sub-sub genre. Just check out Ken Weiderhorn's 1977 cult classic Shock Waves in the meantime.