I liked the idea and it amused me.
Most of the editing was fine - the right sort of speed once it got going. There was too much footage early on of the cat. It was unnecessary and likely to get people to switch off. Additionally I'd suggest you cut out the shots of the cat from overhead. It just looks like, well, a cat and doesn't play well with the "joke" that it's a beast.
As for the security cam footage - what software are you using - most include a "tv" effect allowing you to destabilise the picture a bit. Alternatively, play the clip on your TV screen on PC monitor and film it - you can't get much more realistic than that. Cheap effect, too!

__________________
Tim