Meh, could use some more work
Okay, I know this was your first flash and this was made eight years ago, but by today's standards, this should improve.
The gameplay is incredibly short: clicking only one button (the lights) and there should be extended. Some different methods of killing Seinfeld could work such as a sniper, hammer, burning him, the works.
The graphics could also change. I disliked the bright blue colors, and the opening scene.
There also should be some more animation, instead of constantly using a tween. Like making him move, and having the right timing to drop the lights on him. The sound clip was incredibly annoying.