None of the Saw films have ever been particularly well-received or particularly noted for anything beyond the clever torture traps. However, 2008's Saw V was interesting for being the first film of the series in which Jigsaw's puppet, Billy, does not appear in person (excluding flashbacks). Interesting that one of the most visually distinct parts of the franchise skipped even a single installment. Stay tuned!
it was probably pregnant and not available for shooting.