Quite advanced for a game this old
Fighter Duel is a well produced flight sim that can really be said to be a heavy, realistic flight sim. In terms of graphics it's well, a mid 90s game, so don't expect nothing too out of the ordinary. However, the game runs smoothly in SVGA mode, which means that you can play it widowed in 640x480 mode in a DosBox emulator without issues. The game is mostly about aerial fights, focused on dogfighting. Thus, if this is what you want to focus on you'll really get a good experience. In terms of airplanes, well, there are quite a few included, German and British, of the WWII era. So Spitfires, Mustangs, Corsairs and a few others. The great thing about the game is the realistic way in which the planes behave, their physics. Expect quality approximations of the way the planes behave at different speeds and altitudes and overall, great controls, of course, with the required joystick controller. Absent that, it's a bit of struggle, but like I said, this is a pureblood sim. At any rate, if you liked Chuck Yeager's Air Combat you will find this one just as great too.