Continuity mistake: When Reese is in the police SUV and Gordon is talking to the cop who's wife is in a hospital, the cop is sitting in the front passenger seat holding his gun away from his body, towards the driver's seat (the barrel goes up and to the right). When the shot changes to Gordon, you see a gun barrel in the foreground going up and to the left as if it was coming from the driver's seat.
Continuity mistake: When the Joker is telling Batman that he has Rachel and Dent in two different locations the Jokers hands on Batman's arms differ between shots.
Continuity mistake: After the opening robbery, Gordon enters the vault, and we see the nearest cart on the left has nothing on top of it. But a moment later as Gordon is next to that cart, he drops a file on the cart, next to a stack of money that has appeared out of nowhere.
Continuity mistake: When Lucius Fox is showing Bruce Wayne the new Batman gear, Bruce picks up an arm plate, activates it, six blades flip up and shoot out. We can see as it happens that deep 'holes' in the arm plate show where the blades had been. A second later, when he returns the arm plate to the drawer, the bat-shaped blades are back inside the arm plate, as it is nearly smooth again just like the second arm plate next to it. Two additional arm plates are shown futher to our right with their blades standing up.
Continuity mistake: When the joker is explaining to Rachel how he got his scars a piece of confetti is under his nose, then it is gone, then it is back under his nose.
Continuity mistake: In the final fight, Batman shoots the blades out of his gauntlet to knock the detonator out of the Joker's hand. About a half second later, Batman throws Joker over him and off the ledge. If you pay attention, the blades have reappeared on Batman's gauntlet for this one quick shot. They are then appropriately missing for the rest of the scene. (This mistake goes by quickly, so slow motion helps but is NOT required.)
Visible crew/equipment: When the Joker places the smoke grenade in the bank manager's mouth, a wire or tube can be seen on the left side of his face. It's only visible in the shot when the string pulls the pin, as soon as he drives away in the bus.
Revealing mistake: As the SWAT guy preps a charge, the false section of the wall is outlined.
Revealing mistake: Gotham General blows up but it appears to be an abandoned building. The shot pulls out after the Joker gets into the bus and you can see sky right through the building.
Answer: The gun fires using compressed carbon dioxide as a propellant. The cable is wrapped in a coil around a motorized turbine within the gun. The pulley system in Batman's belt buckle allows him to reel himself in hands-free and still maintain equilibrium. There is a four-pronged grapple at the end of the cable. This is what is magnetized, creating an attraction between it and the monofilament cable. This ensures that the grapple will attach itself to the cable for a secure hold. This is why the magnet itself does not need to be especially strong to support any amount of weight. It also explains the relative ease with which it can be detached and its seemingly "magical" ability to wrap itself around various objects.
Phixius ★