Good and Fun
One thing that works for this is the characters are in Character.
The gang chasing Jimmy just seems like the right thing to be doing and it makes you wonder "What did he do this time?"
The cartoon style of art fits very well with the characters and the setting they are suppose to be from. It has both a simplicity and a sense of complexity all at the same time. I think you have done a good job rendering the characters.
I would have liked to see some ground shadows to go along with them as they were running. And perhaps maybe some burnt marks or something on jimmy and/or on the other characters to kind of show that one of his experiments went haywire.
Great Job
4/5
9/10