Definately needs some improvement.
I think Seinfeld is one of the funniest shows on television, so you got some points for adding some funny sound bites from a few of the episodes. The animation definately needs more improvement, the tweening seemed lazy and the bit of animation you had didn't really impress me.
Another thing that bugged me was how there wasn't a plot or anything really going on. A lack of storyline can make your flash suffer a massive punch, even I have fallen to that fate. Just try to make some more action and animation and the flash will improve by great lengths.
You seem like a funny guy, so creating flashes dealing with humor shouldn't be a massive chore. As long as more effort is put into a flash of yours I'm sure you will achieve great success. Keep up the great work!