Game fits theme really well, having two places to defend from was a neat idea. The rats are really hard to fight against, especially as once they hit the top of the ground you have no way of destroying them with the bombs, whereas the birds you can kite to the edge of the screen to shoot first.
I kept trying to hit space to drop bombs instead of having to move the mouse to the bottom, it might have been a bit less restrictive to separate the controls of the two, however it did create a good tension between the two sides of the defense.
Enjoyable gameplay for the most part.