I really just didn't like it.
Again, I just did not find this enjoyable. I recognize that you did put a good deal of effort into this, but that's the only reason I didn't give you a lower score.
The humor was almost nonexistent. Seriously, I smiled maybe once. The joke dragged on WAY too long, and was too repetitive. The scream sound effect you used wasn't very good, and with each repeated time you used it, it got more and more irritating. The animation wasn't that good. It wasn't TERRIBLE, but it could have been better. I'm not going to take too much off for that, anyhow.
Overall, I didn't think that this was very entertaining, and I had to force myself to watch this. I give it a 2/5, middle of the road. In the future, it might not hurt to invest in a microphone and make your own voice effects, or just try to vary the ones you use.