Pretty fun, but...
When you say you ran out of space for the ending, what do you actually mean? It's a decent toon and probably gave you some good practice with animation, but I'm sure the stuff you make in the near future will be even better.
One thing I actually disliked much more than the ending (which was kind of funny in retrospect, in a Tricky the Clown kinda way) was the lack of characterization. You are clearly going for a certain cartoonish feel in this movie and it seems like you have a cool main character (the zombie hand), but you didn't spend enough time making the character interesting to the viewer, or the side characters for that matter. Why does that one guy have a gun? Is this the zombie apocalypse or is it just one zombie back from the dead?
I like the idea of this hand having lots of character with very emotive gestures, like Thing from Addams Family, and I would spend more time on that. Good luck sirs.