This would need lots more work.
The concept you have is really funny. I like it a lot, however, the way you carried it out was a little bland. I think the cat, even though crippled, should be able to move around easier, but with just as much trouble. Maybe having him constantly scared that something bad is gonna happen to him would be a nice twist. I guess the best advice I can give you is to have you check out the "BEEBO" series for an idea. The way BEEBO acts is different then Stumpy, but it might give you some tips on how to carry out some more funny stuff. Work up on this and it should be really good. Good luck.