Interesting idea - shooting poor little crabs! Ha ha. The gun FX sound didn't quite seem to fit in with the game - it seemed too realistic and violent.
I liked how the controls were very accurate and easy to control with the mouse, but I wasn't sure what to do when I ran out of ammo. It would be nice to have had ammo boxes dropped in or something you could pick up to get more bullets. Also, is there a way to "win"? It seems you just shoot and avoid crabs until you are out of bullets.