This maneuver is very complex.

This problem is very difficult.

The difficulty of this problem makes me scratch my head.

This problem is so difficult to solve, it gives me a headache.

He is good at operating that machine.

This is the most difficult case I have ever faced.

The operator is operating the machine.

The operability of this new software is very excellent.

This robot can be remotely controlled.

It's not so much a big problem.