[mikeash]

Controlling pitch and roll while at altitude is not actually very impressive, no. If you were writing code to do this, you'd probably just slap a PID controller on each axis, tune the coefficients, and be done. You might break 100 lines of code if you like being verbose.

[bigiain]

People have quite significantly more sophisticated control that that running on dinky little 8 bit micro controllers, see Ardupilot at https://store.diydrones.com/APM_2_5_Kit_p/br-ardupilotmega-0...