Those are far from the gamiest maneuvers I've seen in the arena, especially the snap roll.
The only thing I consider completely unrealistic is the "porpoise", the rapid exchange of high positive and negative Gs. I don't think anyone could stand to keep this up for long.
That said, I'll hone to having trouble with maneuvers like this. When people fly smooth "good" ACM, I can often get guns or counter their maneuver. When they do something like this, I have real trouble. I've found guys simply rolling left and right rapidly while 400-200 out impossible to kill without running out of ammo. I don't know why.