This film left me in deep regret for Superhero Movies that were once great, but were smashed by this piece of work. In other words, I don't think that there has been any other film that has destroyed the future success of such a genre through cliche storyline, chroma key slip-ups and sound variations.
Though that first paragraph was full of negativity, I am willing to help through the following advice.
1. Chroma Key: When you shoot your actor/object in front of a green screen, make sure the lighting is adjusted to full blast to make sure that there isn't any shadows or other problems with what is on the screen. Now you know not to wear Green in front of Green, unless you wanted too... :D But one other thing is to use a High-Quality Camera, (HD is PERFECT :D) so that there is no Green-particles when you add the Chroma Key Footage to the background you desire.
2. Story: I was just gob-smacked that you used the "Bitten-to-be-Superhero" story to portray the character, you might know that this has been done many times with Spider-Man and many other films. Also, the "Animals-being-Superheros" Story which is a hard one to keep away from. But if you run out of ideas, then use this for next year's film: A Dragon-Slaying Potato XD
Best of Luck :D