The movie not only overstays its welcome in the big bad world, it stumbles in a much more natural home. "Saw" can be really hard to understand in one take, and at times it doesn't know what to do with itself. The old unifying fear of never being able to call back to your home time in an untimely way is dispelled in this hour-long gaggle of jittery yelps, dank reels, and raspy