It would be really hard to say anything about Ace Combat 6 without first mentioning how stunning the game looks. I've always been a "Graphics Over Gameplay" type person, but holy... the game looks absolutely incredible! Jets are crafted with the same meticulous attention to detail that cars are in most racing games. Plumes of exhaust bellow from the backs of planes and missiles. Even small elements, like the inhale/ exhale of the engines when you throttle up and down, are included.
Cityscapes - something that is usually just a flat mess of textures in most flying games - are the most realistic I've every seen in a flight game. Environments are huge and present a nice sense of scale. You'll even run into touches like cloud cover that you, or enemy jets, can hide in. If you're still looking for a graphical showpiece, this is it.
Though visuals tend to get most of the attention, audio is another strong point. Some of the dialogue sounds overdramatic and a bit weird thanks to awkward lip-syncing, but the orchestrated soundtrack could easily match up against most motion picture soundtracks. This is especially true about the melody of the main theme, which pops up in the oddest of places and always manages to seem right at home. It is easily one of the more stirring themes to come from a videogame in the last few years.
However, the soundtrack isn't even half the overall experience. As you play through missions, your radio is constantly bombarded with chatter from your squadron. Mission updates and attack warnings come in on the fly and are delivered with a sense of urgency, setting just the right tone for the game. Even "slower" moments have a rushed exciting feel thanks to the dialogue. Some of it manages to pull you in so well that you'll actually get a little disappointed or angry with commander's orders.