Nice concept but short
I really liked the concept of the way they tried to kill him, and I've never seen something like that before, but it felt like it was missing something.
Part of that might be that there wasn't really a good punchline in the animation, and the flash itself was a bit short in my opinion.
I would recommend for something like this, to show it to your friends before you post it on Newgrounds, and then from those reactions try to fix the things that bring the flash down a bit. But overall it still brought something new to the flash and that is of course the most important thing.