Unoriginal, but well executed.
I have not played the game, but if the description is to be trusted, this isn't very original - points off for that.
That said, the animation itself was great for what it was. While the content technically isn't yours, it was still reasonably well executed. I wouldn't call it outright "stolen", but your part was merely as cosmetic one - most Flash animations would be judged largely by their direction, yet, in this case, it is a null point.