In the opening scene, Ben is standing behind the desk and he rips the phone out of the wall and throws it across the room in front of him. And then, still standing at the desk, he puts the gun under his chin and pulls the trigger (still facing the phone) and yet the phone gets splattered by blood.
When Linda is repeatedly calling Ben in the opening scene, the phone says it's 11:03 each time it rings, despite more than a minute passing between the first and last time it rings.
Contrary to Dean's opinion called I.D is not "over 100 years old". It was invented in the 1960's and patented in the 1970's.
When Dean says the name of the town, he pronounces it "Mi-LAHN," like the Italian city. The Ohio town's name is pronounced "MY-lan."
When Dean is putting the gun down, he ejects the magazine but doesn't continue with proper procedure by clearing the chamber.