Another round of thrill killings, maybe the same thrill killers as in the first movie? I don't know. It's been like, six years for me. Ten since the movie itself was released! Why we're sequeling it NOW - with a perfectly decent, theatrically-released movie no less - I don't know.
These killers pass up a lot of opportunities to kill their marks, so I guess it's more about savouring the flavour than racking up a count. They, like the filmmakers, seem to like staging horrible violence to the sound of upbeat (or at least bombastic) pop songs from the 80's. There is more than enough of this.
But it basically works, with a fresh-ish new setting and a core family that's believable enough, like an old slasher movie with almost as many killers as victims and better filmmaking chops.