Continuity mistake: Meg Ryan and the bloke she was going to marry first were picking out colours for the house and he points to one but when he mentions later on he points to a different one.
Continuity mistake: Towards the end, when Tim Robbins is chasing the President's car, he stops by Einstein's house first (he is wearing a red jacket). When they show a close up of his hand knocking on the door, his sleeve is blue. When they cut back out, it's red.
Continuity mistake: When Meg finally realizes her feelings for Tim she puts her legs on his lap. The angle changes and she does it again.
Continuity mistake: When Tim Robbins and Meg Ryan are on the balcony looking at the stars, the camera is doing a shot from the front - Tim is on the right and Meg is on the left. The camera then does a shot from behind them and Tim is still on the right and Meg is still on the left.
Continuity mistake: The scene where he gives his lecture before being called out you can see 3 small measuring instruments on the wall on the right below the board. Once Ed begins to mumble during his lecture there are only 2 instruments on the wall, and they've been moved.
Continuity mistake: When Meg, Tim, and Walter are on the sailboat, from one angle (facing forward) the water is smooth whereas from the other angle (facing aft) the water is choppy.