Hunt the forest for all sorts of animals. There are secret objects what will get you bonus points as well as you can lose points by shooting the wrong things. Try to unlock different skin types by completing each levels.
Shoot down the enemies with a handgun or sniper rifle. Don't let any of them get away as you move onto new levels. Note: It takes awhile to load from blank white screen.
Strike down the enemies once again with a pistol or a sniper rifle. Don't forget to shoot the bomb within 2 seconds otherwise it'll explode and damage your health.