In the final scene where Walt is touching the cylinder, his hand is placed to the right of the grey/black knob. When the ceiling camera pulls away, the bloody hand print is on the left side of the knob.
When Walter throws down the cell phone after talking to Lydia, the phone changes locations on the ground between shots.
When Walter is assembling the mechanism in the desert for the sweeping machine gun, he uses ratcheting wrenches as the bars in the sweeping mechanism. When the same machine gun is shown operating in the trunk at the club house, there are plain bars used in the construction.
After the machine gun in the trunk stops firing, we see a top down shot of Jesse and Walt on the floor, with Jesse on Walt's right. When the shot next switches to Walt getting up, Jesse is on his left.
When the M60 runs out of ammunition the view into the boot of the car shows no fire inside. When Todd peeps out through the blind there are flames in the 'slot' cut by the bullets.
In the beginning of the episode when Walt is sitting in the car and we see red and blue lights as the police arrive. In New Hampshire police vehicles only have blue lights, red lights are reserved for emergency vehicles.
The ricin in Lydia's coffee wouldn't have done any harm to her, since it's a protein and would have been neutralized.
Early in the episode a close-up reveals the stolen Volvo's New Hampshire license plate. All New Hampshire residents require a sticker placed in the top corner indicating the registration for the vehicle is valid, yet this license plate bears no such markings.
When Walter arrives at the neo-Nazi camp, his shirt was completely pulled out of his waistband to prove he wasn't wearing a wire. After the bloodbath and after Jesse drives off, when he pulls his jacket aside to look at his blood-soaked shirt, the shirt is neatly tucked in.
As Walt is brought into the clubhouse, he is shown tucking his shirt back in before Jack starts threatening him.
In the pilot episode Walt is celebrating his 50th birthday, S5 E4 Walt turns 51 and on the series finale he turns 52. However, it isn't until S4 E10 that Walt Jr, aka Flynn, celebrates his 16th birthday and in the finale episode he is coming up in his 18th birthday. The entire span of 6 seasons was to take place in 2 years of story line.
Why this is wrong:
If Walt Jr's 16th birthday is before Walter's 51st birthday, then Walt Jr's 17th birthday is before Walter 52nd birthday. Walter told Gretchen and Elliot to give the money on Walt Jr's 18th birthday which was coming up chronologically speaking.
When Walt enters the snowy car in New Hampshire the snow stays stuck to the drivers side window when he opens and closes the door, but after he finds the keys he clears the snow by simply hitting the inside of the window. If the snow was holding that lightly to the window it would have fallen off when he closed the door upon entering the car.
When Walter steals the Volvo 240, his hand can be seen activating the wipers to clear the snow off of the windshield. Despite making the motion with his hand, he never actually touches/moves the wiper stalk.
When Walter White (Bryan Cranston) has his hand on the cylinder, the reflection shows him suddenly collapsing, but if you look at the bottom part of Walter's reflection, you could clearly see that Cranston did not collapse, but instead simply ducked. You could even see the top of his shirt, and a little bit of his hair.
At 47:28 -"blood" splashes onto the camera lens.
At minute 25+ Walt is in the desert making what is later revealed as his improvised mobile machine-gun emplacement. His power source is an automotive battery, which he connects by first attaching the negative lead, then the positive. This is inconsistent with Walt's character. As a scientist with a meticulous approach to all things technical, it would be unthinkable. He would surely follow the rule long accepted as correct and safe for battery work: to disconnect, remove negative first; to (re)connect, attach negative last. The sparking around the positive terminal demonstrates the point.