Continuity mistake: When the cat's tail is in the sink's plug hole, Ralph is standing by a switch and you can see there is nothing on it, but in the next shot the word "Disposal" just appears from nowhere, and when the cat is picking up his fur from the plug hole, the wording has gone.
Continuity mistake: When Ralph is ready to surprise Alice, there is a switch by the door. But when Ralph tells Ned to bring in the cake, the switch has gone.
Continuity mistake: When Ralph is walking up the steps to his apartment, he has a present in his right hand. The present disappears when he goes through the doors, but re-appears when he enters the kitchen.
Trivia: When Ned is launching Ralph on the bottle of champagne, the label on the bottle says "Selzer's Champagne Extra Dry" - a reference to the Warner Brothers producer Eddie Selzer.