I remember this movie where the plot is similar to Saw but I can’t remember part of the name or actors, a saw it with my friends (2006-2008) and it was supposedly Saw III.
The movie starts with a young woman who walks through a floor full of crystals (no shoes), push a button and returns but now she has to plunge the head inside a fish tank full of acid. Then, the police arrives and found the body. Later, there is a group of young people and some guy who is like jigsaw but without the mask. And the rest can you imagine.
Also, I remember some deaths:
*A guy explodes because he had a bomb in the ribs and he needs to take out.
*A girl with rats and a cellphone.
*I think two brothers, or a couple, whose are tied in opposing chairs with two drills and two buttons. If someone push a button, one drill start to move directly to the head, so one of them have to sacrifice to save the other.
*A guy in a dark room, surrounded by shotguns.