Added more sound effects. Added initial weapon muzzle fire logic.

AlientAttack.MonoGame/Things/Items/Rockets.cs

@@ -2,6 +2,8 @@
 
 internal class Rockets : Item
 {
+    protected override PickupKind Kind => PickupKind.Rockets;
+
     public Rockets(int x, int y) : base(x, y)
     {
         TextureName = @$"Sprites\Powerup_Rockets";