It needs some improvement!
I agree with the last reviewer, it does need some improvement and some of the characters say nothing, I liked how you made details on the characters though lol but you could do another with a section for each character:
for example:
Stan
Kyle
Cartman
Kenny
Chef
Butters
Wendy
Terrence and Phillip
etc...
well for your first movie it wasn't bad, keep up the good work and South Park rocks!