Fighting Carpenter
When you are trying to beat carpenter, use martyr and make sure you have a flame thrower and rocket launcher. As soon as you get to him, use the rocket launcher to blow up the electric chair (about 6-7 direct hits) then switch to the flame thrower. Run like heck and spray him with the flame thrower when he stops to try and cut you. Takes a little while but i found this technique to be the most effective.