Yikes!
This is an old game, that much is clear to see. However, this doesn't excuse it from being so shoddy looking. The graphics here are simply atrocious, no doubt about it with visuals straight out of MS Paint! The gameplay itself is distinctly average, slightly annoying with the fact that the enemies are constantly juddering around the screen, seemingly at complete random.
There is potential here, but the visuals need to be touched up big time, as well as making the enemies act a little more logically, meaning you don't have to chase them all over the level 20 times over. Collision detection with things like the cannons and trees would be good too, as even though the bird is meant to be flying, and I accept it could be flying over them, the people you are attacking can just walk right over them.