Three lost sailors are stuck on a remote island, not knowing that it is controlled by Karl Berger (aka Karl the Butcher, or "der Meister" as he is now known) and his son Karl Jr. They have an "army" of psychopaths called the Infantry of Doom, with a variety of small arms.
How to describe this movie? Just to give you an idea, here is some sample dialogue:
Condemned prisoner -- You'll burn in hell for that! Karl the Butcher Jr -- This IS hell!
This is the last of Andreas Schnaas' Violent Shit trilogy. It's better if you're survived the other two (which are actually harder to find). But even by itself, it is quite a gore-fest. The Violent Shit trilogy really is the closest thing to hell that I've ever seen on film. Despite the crude special effects, campy acting, and amateurish photography, it's an experience you will not soon forget.