Well if the birds did "fry on sky" at least that would be more entertaining than what's going on with this game. Good concept so expand and run with it. There are thousands of birds to choose from, you could really have fun making this game really hillarious or really scary. Showing birds that chase and peck or birds of prey that dive, grab with their tallons (birds toe nails) and fly away with their prey in it's grasp. Ding, ding, ding it's dinner time.
Short version
1 use differnt types of birds
2 use different types of weapons
3 use different types of items that the birds drop
Sorry, if this came across mean, I feel the game has potential for improvement.