Plot hole: The children decided that they hated the Powerpuff girls in one day. Then how did they have supervillain costumes and a van? The mom said they had lots of time to prepare.
Plot hole: I don't think the police would throw the wife and children in the same jail cell as Harold.
Continuity mistake: When Marrianne calls Harold to the table, the plant in the middle disappears as they climb on top of it.
Revealing mistake: When the van drives upstairs, you can see that it wasn't destroyed.