Continuity mistake: When Edgar takes Duchess and the kittens to be abandoned in the countryside, he is on a motorcycle and sidecar combination. During the trip, the sidecar changes from one side of the bike to the other and back again. Also, when the sidecar separates from the motorcycle while the dogs are chasing Edgar, the wheel on the sidecar switches sides regularly as well.
Continuity mistake: When the Winter Warlock's icy heart melts, he is holding a toy locomotive with its front showing, but the next shot shows the locomotive's rear showing.