Continuity mistake: Dabney Coleman is chasing Tom Hanks and Lori Singer into the Senate Office Building and in one shot has his flip-up shades on and the next shot they're gone. All in an impossible split second.
Continuity mistake: The two CIA guys are watching the softball game and report the it is the bottom of the ninth - the Senators are winning. In the next scene the Senators are batting. If the Senators are winning why are they batting?
Suggested correction: The Senators are never seen batting. Richard (who is on the Senators) is playing in the infield and lets a ball go by, then the next batter hits him in the head with the ball. After that, Maddy takes him home and as they're driving off, it appears the game is over, presumably with the home team winning, and both teams and umps are gathered on the field talking to each other.
Suggested correction: Tom Hanks play on Senators, and is "out", and opponent is batting. Senators lead 1-0 but opponents 9th field is still blank, so they can win. That's why they play.
Continuity mistake: During the ambulance scene, the inside of the ambulance is shown as driving around with the transmission in park.
Continuity mistake: When Richard is chasing Maddy and the old couple on Morris's bike, you can see that the handle bars are bent on the left hand side. As the chase scene goes on, the handlebars change from being bent to straight several times. (01:15:20)