It's easy to see exactly what was improved in the newest installment of the Ace Combat franchise.
First off, the first thing you'll notice as soon as the dogfighting begins is the smarter enemy AI. The regular no name aircraft even present themselves to be scarily intelligent. F-18s have been spotted using flares, and the SU-37 pilots might try to "cobra" their way out of danger. Using manuever after manuever, trick after trick and will even send one plane as a decoy while the others gang up on you just to get on your six by any means necessary (and we're talking normal mode). The rival aces on the other hand, won't greet you in those large numbers like the infamous "8492" or "Yellow Squadron" but that doesn't take anything away from their difficulty to engage.
Graphics, Ahhhhhh yea the view from up there is great with vivid scenery and ground textures that blows AC5 out of the water. Detail has been added to this part of the game even more so than before and you'll notice the difference even at low altitude flight. The weather effects are even more realistic and clouds, oh yea the lovely clouds, use your instruments wisely because if not you may end up smack into a mountain or wall. Explosions have gotten much more work added to them, from a plane crash or a 'fox-two' and water explosion all have a different animation than the last AC.
Gameplay now I have to say the wingmen really do listen to your orders now. If you tell him to disperse, a while later he may be on another side of the map racking up all of the kills from you. Yes they are that skilled. The feel of the aircraft is slightly different from AC5 in which they feel more stable to fly without the over exaggerated pitch or roll when turning.
Also another important factor is the sense of speed. The sense of speed in this game is enhanced so things tend to fly past you a little faster than before.
Of course all games have its' flaws, and for this one it's not so much as what in the game, it's more about what's missing from the game. Online play, the key feature that would please every combat fan thirsting for Squad battles. Another thing that's still missing from the game is more realistic takeoff/landing physics, but overall Ace Combat Zero: The Belkan War is near perfect for any flight fan or newcomer.