First trap: There was no tape explaining anything. We're led to believe that this was the start of Jigsaw's planned game following his death. However, this trap didn't seem to follow Jigsaw's methods so it seems like it was set-up by somebody else, but by the end of the movie, it was indeed set-up by Jigsaw apparantly. I'm unsure really.
Art: He passed his test only to get RE-tested, WTF? Plus I didn't like how he was a trap victim because of him mainly being a lawyer. Defending criminals is his JOB. If Jigsaw feels that way, he might as well test every lawyer out there.
Rigg's game: For him to pass his game (which was just a carbon copy of Jeff's game), all he had to do was nothing? Lame. I also didn't the fact he got to run around the city. Jigsaw's M.O. is to capture somebody, stick them in an enclosed location, and they lived or died, usually at the cost of a sacrifice, period.
Trap victims: In the other movies, they would reveal what their names or at least what their crimes were. In SAW IV, they did a very poor job here. I didn't know who half the victims were and as far as I know, some of their crimes weren't even revealed like the guy who had his eyes wired shut. Very poor characterization and lazy writing in my book.
Transition Shots: While I enjoyed them in SAW II and III, they went overboard with them in SAW IV. When you do them in the middle of a trap going on or start having flashbacks WITHIN flashbacks, there is something very wrong there.
Eric Matthews: They should've kept him dead. The whole fight with Amanda and her killing him is what caused her to evolve into a serial killer. By changing that, you betrayed the character development. That's like saying Batman became Batman, even though his parents survived the mugging.
With how much the emotionally unstable Amanda hated Eric (the guy who framed her so she went to prison, beat the sh** out of her, tried to kill her, and then continued to berate her afterwards), she would've made DAMN sure he was dead!
I just felt like Matthews being used again was needless as he served his purpose in the past 2 SAW films instead of being used as sequel bait AGAIN. It was more fitting he died because he couldn't keep his mouth shut still being Mr. Tough Guy instead of hanging around for a couple of hours, being a whiny wimp.
Oh, and his death was over the top and stupid. The worst part is he died without even know what happened to his son. Some people say his fate should've been left ambigious and I could agree with that.
Jeff: They had an interesting storyline set-up with Jeff and they literally copped out on it. Again, lame. Just because it was a surprise doesn't mean it was a good one. (If anything, Jeff's second game should've been the opening sequence where he rescues his daughter, but dies in the process.) Also, Jigsaw planned Jeff to die even though he also planned a second game for him, WTF? Oh, and Jeff had an equally stupid death.
The time twist: The same time crap ruined the movie. It complicated SAW III's plot, created more loopholes, and essentially doesn't work (Jigsaw is soooooo smart that he could time exactly WHEN people like Strahm would act? ********!). It's bad enough that Jigsaw plans long enough just for one game. I couldn't take it seriously that he would play two major games at once. Plus it cheated the audience because it wasn't Jigsaw's final game as we had gone to see the movie for.
The final twist: I didn't have a problem with Hoffman, but the fact Jigsaw apparantly has a THIRD apprentice is stupid. I know Jigsaw always has a Plan B, but him having further more than that is just ridiculous.
Final thoughts: The biggest mistake was taking Eric and Jeff, the main characters from past films, and killing them both off in the SAME movie. Great way to piss off a majority of your fanbase! To me, they might as well just have given us the middle finger.
SAW IV would've been better if it was a direct sequel. If Rigg's game was solely masterminded by Hoffman, that would make perfect sense and explain all the inconsistencies I mentioned since it shows that he doesn't follow Jigsaw's patterns exactly. Maybe he's still learning or he's purposely deviating or adding in his own Jigsaw elements?