When the truck driver honks his horn, the sound of an air horn is heard. In order to sound that horn, he would have to pull a cord. Pressing on the steering sounds the city horn, which has a different sound.
When Rick Ricker checks his symptoms on the Internet, the dialog box shows the question "It's okay, you can tell me the truth. I'm a Doctor" with no options. The camera switches to Rick's face, then back to the computer with an option on the screen.
When Rick is fighting with the thug and the gun continues to go off, he hits two street lamps that fall on his mom and dad. When the thug runs away and Rick runs to his father, the street lamp is not on his head, or even in the shot. When he accidentally shoots his mom, the lamp is not on her head.
When Hourglass loads software to destroy the world, he puts a Windows CD into his Apple computer. He may have been running a Windows emulator, which allows Macs to run Windows software. Recent versions of Mac OS include a Windows emulator.