Other mistake: The physics of what happens to the mallet after it hits the ring are completely unrealistic. No matter what the actual composition of red kryptonite contains, there is no way that it could reflect all of the force that was impacted upon it. Clark was also weakened by the green kryptonite. Jonathan's swing of the mallet and Clark's weakened strength would not have allowed him to keep his arm out after being struck by the mallet.
Continuity mistake: When we first see the meteorite tattoos on Wade Mahaney, they are all green. When Clark sees Whitney's tattoo, it is plain black. It was also faded, which means it's not a fresh tattoo. Whenever Clark runs into the other guys, he feels the effects of the meteor rocks, but never when he is alone with Whitney.
Plot hole: When Clark uses his heat vision to heat the metal door handle to prevent Desiree from escaping, he only heats one handle. I know that things were happening fast, but it wouldn't have taken him that much more time to heat both handles, which he should have done since there is no way he could have known that she would have tried that particular handle.
Factual error: Clark lifts Chloe's car by the back. He is only holding on to the very back left portion of the car, yet while he's turning it, the car is completely horizontal. The front of the car would buckle since it weighs so much and isn't being handled by its center of gravity.
Plot hole: Though it fits the general plot of Davis always being first on scene, in the real world no on-duty paramedic drives the ambulance alone. There will always be a minimum of two EMTs per ambulance, one to drive and one to tend the patient. The only time a paramedic or other EMT will be alone is if they arrived on the scene in their own vehicle.