Hangsim surprised me at how stable and virtually bug-free it was out of the box. The game installed easily and detected my 3D video card. The graphics use D3D acceleration and look excellent at 800x600 all they way up to 1280x1024. Frame rates were smooth as glass until I added about six other planes to the equation then things started to bog down a bit. Some of the major cities feature buildings, which actually spring up from the terrain when you drop to lower altitudes.
Sound effects are excellent.
You can hear the wind whipping past your ears or through the cockpit glass if you are in the glider. The buzzing of the props on the powered kites gets a bit annoying, and the frequent beeping of the Stall Indicator is even more annoying giving you a good incentive not to stall your aircraft. Nice little touches like a personal logbook and a Flight Analysis module lets you evaluate your flight performance and display the results in a graphic format. It is a great tool to help you smooth out your controls of the plane. I spent several hours trying to turn my jaggy line graph into smooth arcs.