code: function (dt) {
  
          // just manually change the guy position
          this.pos.x += 0.3 * dt;
  
          // repeat once leaving the viewport
          if (this.pos.x >= me.game.viewport.width) {
              this.pos.x = 0;
          }
  
          // call the parent function
          this._super(me.Entity, "update", [dt]);
  
          return true;
      }
docs: manage the enemy movement