code: function (response) {
          // res.y >0 means touched by something on the bottom
          // which mean at top position for this one
          if (this.alive && (response.overlapV.y > 0) && response.a.body.falling) {
              // make it dead
              this.alive = false;
              //avoid further collision and delete it
              this.body.setCollisionMask(me.collision.types.NO_OBJECT);
              // set dead animation
              this.renderable.setCurrentAnimation("dead");
              // make it flicker and call destroy once timer finished
              var self = this;
              this.renderable.flicker(750, function () {
                  me.game.world.removeChild(self);
              });
              // dead sfx
              me.audio.play("enemykill", false);
              // give some score
              game.data.score += 150;
          }
  
          return false;
      }
docs: collision handle