Can someone please explain why this is difficult? I think its trivial but I am often wrong about these things. It's got an accelerometer and a gyro. Doesn't eve

Can someone please explain why this is difficult? I think its trivial but I am often wrong about these things. It's got an accelerometer and a gyro. Doesn't even need vision to do this. Even simpler would be just a hard-coded program without a feedback loop except after the end of the stunt to level out the quadcopter.