You have to hold down the mouse button until the bullet travels to the enemy or else it doesn't kill them. :/ Incredible time consuming and unentertaining.
As stated, the physics are pretty bad.
Also, for someone starting out, you might want to slow it down a little bit. I felt like I was in a car wreck. I got to -10 before I figured out what to do.
1/5 'cause I can't give you a 0 and I like the font. Oh, and way to have facebook :S.
Definitely interesting. Not sure what you were ingesting or inhaling when you came up with the idea for this game. I'm not a huge fan of shooters, but maybe increase the sensitivity on the ducks. I hit one about 20 times and I guess it registered as a miss.
Also, on the menu, maybe choose a different color than orange for your font. It's a little hard to read.