Hi, the latest code should solve this https://github.com/pocketmoon/MPU-6050-Arduino-Micro-Head-Tracker/blob/master/Arduino%20Sketch/MPU6050Joy/MPU6050Joy.ino
You can invert axis in code on line 516/517/518 by sicking a minus sign in from of iX or iY or Iz. But I usually just invert in-game (using the invert axis checkbox in the controller config if needed).