Fix issues

Scripts/SingleShot.cs

@@ -0,0 +1,16 @@
+using Godot;
+using System.Linq;
+
+public partial class SingleShot : Projectile
+{
+   public override void _PhysicsProcess(double delta)
+   {
+      var pellet = GetChildren().OfType<RigidBody3D>().Single();
+      pellet.Translate(new Vector3(0, 0, Speed * -(float)delta));
+   }
+
+   private void OnBulletHitObject(Node node)
+   {
+      QueueFree();
+   }
+}