Basic Gameplay: Fly around in your plane and kill enough enemies to clear the stage. There are five stages and three levels of difficulty. The differing stages change what types of enemies you will face. Your enemies will be either airplanes or balloons. There are different types of each and they all have different amounts of health and behaviors. All fighting occurs on a 2D field. This is a good thing. Airplane fighting games have a major flaw in that you spend half your time circling and the other half jousting. Having a 3D playing field means even more time spent circling so a 2D field is a good move. That said, AeroStyle is still an airplane dog-fighting game and the fact is you will spend a lot more time circling than shooting and dodging. Speaking of dodging, you dodge by clicking the right mouse button, this will send you into a barrel-roll or a loop-the-loop and will make it so the incoming enemy shots miss. These maneuvers tend to throw you off your firing vector so using them means more time circling. If you're really into the subtle intricacies(I'm assuming they exist) of airplane dog-fighting, then you will probably enjoy the gameplay. If not, you may want to turn your plane around and fly somewhere else.
Graphics and Sound: AeroStyle is old. As such its graphics are old. The models are incredibly low polygon and the textures are incredibly low res. It isn't pretty but it isn't particularly ugly either so the graphics really just do their job of giving you a visual representation of the game's state. You shouldn't judge a freeware game too harshly on dated graphics anyways or you'll miss a lot of the true gems that are out there. There's no music. The game sounds are adequate.
Controls and Recommended Options: You shoot with the left mouse button, dodge with the right mouse button. Moving your mouse to the right and left side of the screen turns your plane. How sharply you turn depends on how far you move the mouse. I find this to be a difficult and annoying system to use but you do get used to it after a while. F1 toggles full-screen mode (this also turns on the display that shows you how hard you're turning), F2 toggles how the ground looks, F3 toggles the ground, and F4 toggles the stats display. I recommend playing in full screen. The other settings won't really make a difference.
Conclusion: I'm giving this a C because in my opinion, shooter gameplay simply does not mix well with airplane controls. AeroStyle, however, does a better job than most games at mixing them (largely because of its general restriction to a 2D playing field) and as such deserves a passing grade. If you enjoy airplane combat games, go ahead and give this a download. If not, don't bother.