Goofs

Before Mike tosses the shoes on the power line, he stuffs the drugs in the toe of the left shoe. Later, when he uses the sniper rifle to shoot the shoe so the drugs can pour out on the the delivery truck, it's the right shoe that he shoots and the drugs pour out of.

When Mike takes the sneakers from the package, one is 1/4 laced up, and the other 1/2. He ties them together, stuffs the drugs in and throws them on the power line. But when he shoots, both are tied the same amount.

When setting up the shot at the red trainers, Mike stuffs a bag of drugs into the toe of the left shoe, but it's the right shoe that he shoots to shower drug powder on the truck when the shoes are dangling from the power line later.

There was no recoil from Mike's sniper rifle when he fired it.

Mike Ehrmentraut, a trained sniper, is shown setting up a shooting position that is revealed by sunshine reflecting off of the binoculars that he is using. Not only would a sniper not choose such a position, they wouldn't attempt to make a shot facing the sun unless they absolutely had to. In this case, there was no reason to shoot from that position.

Before we see Jimmy smoking, almost at the end of the episode, Kim is working on her computer and she is using a cordless mouse, not generally available in 2003/4.