It's an amazing game, I only have a few suggestions to make it 5 stars.

1. The dog popping out with the duck that has been shot and the music that goes with it.

2. The sound doesn't really let you know exactly where the duck is.

3. The gun is a lot louder than everything else.

4. The option to also have the orange gun, maybe duel wield guns?

5. The music in between levels