OK, what was I expecting anyway? The same thing as Saw I... And that's what I got, but less so. As in the first iteration, in Saw II a darwinish serial killer 'tests' people to see if they can overcome their pitiful human failings and survive. Most don't.
It's fine as a rental. I was entertained in the way that a newspaper caught on the wind is entertaining. It really depends ones frame of mind. Compared with staring into the pitch darkness, it was fascinating.
This flick is a bit of a money grab... But if you go in knowing that, it's not so painful.