These legendary planes aren’t just slop thrown together by a couple of 13 year old Nintendo fanboys. As with the first WOP, Shockwave boasts “absolute realism” technology. At the heart of the company’s claim is the challenge to the hardcore element of the flight sim community that you can pick up the real flight manual for one of these warbirds and fly the WOP II version “by the book.”
Having never piloted a real plane, much less one of WWII vintage, I can’t personally vouch for their claims of absolute realism. But having read my share of technical manuals and flown every manner of flight simulation since the days of legendary developers such as SubLogic, Spectrum Holobyte, Microprose, and Dynamix, I can say that WOPII’s flight modeling is utterly convincing. 
The Zero turned tightly, especially at low to moderate speeds, which is exactly what it is supposed to do. The Bf 109 was less than stellar in horizontal maneuvers, but its vertical climb capability was extraordinary--where the Spitfire would stall out, the German Messerschmitt kept climbing.
I have to admit that my first go round in the American P-51D Mustang was disappointing. On the first flight, I thought it handled like a pig, which belied its reputation as one of the smoothest fighters of the era. But then, I found out the problem was me. WOPII models fuel/oil mixture. Get it wrong and you’ve got performance problems. I even tipped the Spit and Mustang nose down into the tarmac at takeoff a couple of times because I went full throttle before releasing the wheel brakes. And the Mustang’s torquey engine on sudden throttle up at takeoff, demonstrates a strong urge to pull to the left (like the car I drive, only a hundred times worse).