When the baby eats the chili, she knocks the can on the floor from her stroller and it makes a clank sound as if hitting a hard floor. But it lands on the carpet and there should not have been any sound coming from an empty can landing on carpet when dropped from a height of just a foot or so.
During the poker game Jack and the neighborhood ladies are playing when Caroline arrives home from work, the ladies all quickly get up to leave upon Caroline's arrival. In one brief shot, there are a group of "other" kids in the living room in addition to the three Butler kids. These kids presumably belong to the poker ladies. However, not a single one of the mothers walks out with their kid. Granted, they could have come back to get the kids. But it would have made a lot more sense to do this the first time.
When in the car at the grocery store and the kid pulls the gearshift down, he pulls it way down past the reverse selection to one of the forward gears yet the car goes backwards into the shopping carts behind them.
When Jack first meets Ron, his chainsaw is making loud, typical chainsaw sounds as if it is fully engaged (saw on, trigger pulled). However, the actual chainsaw blade alternates from not moving at all to moving very slowly--indicating that the saw is either idling or not even turned on.
In the last scene of the movie we see the Tuna commercial, which had been shot the day before, playing on the TV. It would be impossible for a commercial to be shot, edited, finished and delivered to any particular network for airing all in less than a 24 hour period.
While Jack is in the basement trying to stop the washing machine's spraying water hoses, Kenny is yelling for help upstairs. As soon as he gets the water shut off, Jack turns quickly to run upstairs, using the concrete wall for support. As he pushes on the wall, the top moves out of place showing it is only a prop anchored at the floor only. As soon as he lets go, it bounces back into position.