Really good movie.
the later ones in the series go full like gore-no torture porn style, and that's fun in its own way, but its so much harder to recommend, because you need to sort of have a specific idea going in to like the later Saw movies. Even by the second one its starting to lean into this kind of thing.
The first one is literally just a really good thriller movie. Probably because they didn't have the budget to be as over the top as they later were.