Almost there.
I don't know if it's just me, but I'm not getting any sound whatsoever. And it's a darn shame, because with a bit of sound this could be even better. Naturally, I suppose, but still.
I like your art style-- a new take on the stick figure approach. The animation could be a little smoother, and maybe take out all of the unnecessary movement. Like when he's rolling on the rooftops. Come on, that's just a huge corn fest.
Maybe for the plot, you could have made it clearer as to just what's going on? From what I can tell, some guy was injected with some presumably experimental drug and now has super strength, and feels like he needs to go on a rooftop-rolling rampage five years later, killing people in a large building. No, it doesn't seem very entertaining.
The backgrounds are maybe a little oversimplified, even given the rather simple art style you have. Everything but the background seems to blend in, but those rectangle shapes with windows just turn me off. I can understand your color scheme, that's not what I'm referring to- maybe look a little in to that.
Regardless, hopefully the next entry in to this series will work on some of the flaws. <3