Still can't figure out the ending of Saw 2 ( please help me...)

Rating: Null/10 (4 November 2005)

Hey Guys: I've been reading all the online praises of Saw 2.
I've viewed the film twice and still can't figure out what's going on.
As for the main body of the film, I thought it was weak.
Jigsaw was compelling, but beyond that, everything was formulaic.
Saw (one) had the advantage of introducing the compelling character of Jigsaw along with his methods of killing and torture. How would he kill the next victim and where would they be when they died? What escape would be offered? Suspense was there.
But Saw 2 seems to go back to the same one trick pony.
Opening scene with the "Informer" was great, but also gratuitous and derivative of the first Saw. (Shawnee Smith's head gear..) How many times was a spring loaded door used as a device of suspense? Four times.
How come Amanda and Daniel escape the gas? Not explained.
How does Daniel move from the Saw One dungeon to the safe? Not Explained.
What happened with Addison and the plexiglass cube? What happened to her hands? Never resolved.
What is the purpose of putting Cop Eric in the Dungeon? What lesson is he being taught? Not explained or resolved I just can't figure out how I missed so many loose ends.
I'd really love to have someone tell me what I missed.
I want to be a fan of Saw 2, but for the life of me, I cannot figure out the continuity or ending.
Please, please help me understand this movie Seaview52@yahoo.com