Other mistake: Quinn is watching the video of the basketball returning from the vortex. The video shows him catching the basketball, then we see a shot of Quinn pressing the fast-forward button until he shows the basketball to the camera and says "and the crowd goes crazy!" The problem is that even though he pressed only the fast-forward button, the video fast-forwards from a point before the basketball came out of the vortex, which is impossible since Quinn never rewound the tape.
Other mistake: Quinn's alarm clock turns on, then about 8 seconds later we see the time change from 7:59 to 8:00. All clock radios turn on when the time changes, or possibly fade in slowly a few minutes before the alarm time, not a few seconds before.
Other mistake: Rembrandt is being tried in the People's Court. When he is sworn in, the bailiff ends the oath with "so help you God?" In this Earth alternative, the US is under Communist rule. There is no way God would be a part of an oath.
Chosen answer: Quinn's brother was going to be a recurring character, so "introduced" in this case referred to the actor becoming a semi-regular.
Jean G