Continuity mistake: When Sam is walking to the door of Emma's house, he is holding a box of chocolates in his left hand and a bunch of flowers in his right. When Emma opens the door and sees Sam, the chocolates and flowers have changed position.
Continuity mistake: When Sam is on the ground after being crushed by the piano coming down the stairs, Sam's eyes are open but in the next shot they are closed.
Continuity mistake: When Sam is knocking on the door after losing the duel with Bugs, there is a doormat under his feet. But when Bugs (dressed as Emma) opens the door, the doormat has gone.
Continuity mistake: When we see the Center News building at the beginning of the cartoon, you can see that there is nothing on the left window, but when we see Sam reading a newspaper in the next shot, there are now two pieces of paper on the window.
Continuity mistake: During the wedding sequence towards the end of the cartoon, you can see there is no one in the pews when Bugs and Sam walk down the aisle, but when we see Bugs' wedding dress being torn off in the next shot, people have appeared.
Continuity mistake: When Bugs and Sam are duelling with their pistols, Sam marches out on the road and is run over by a bus. You can see Sam is holding his pistol when he is run over, but after a quick cut to Bugs we return to Sam, and his pistol is nowhere to be seen.