I just finished playing the AC:AH demo on 360, and thought I'd write up my thoughts here, on my favorite video game website! This is probably a better place to post it than on Google+, Facebook or Tumblr, anyway. (and too long for Twitter)
I've owned and played Ace Combat 4, 5, 6, Zero, and the first PSP one, and enjoyed them all. I think they are making some changes to the formula now that they have a little competition in HAWX. AC:AH overall looks more gritty and is set in the real world instead of the fantasy worlds used in the previous games.
The demo has two levels from the campaign. The first is a fighter level where you fly a F-22 over Miami Beach, shooting down Russians in Su-35s. This is pretty standard Ace Combat style play until you get into Dogfight Mode (DFM). DFM is what you've probably seen in the trailers, where you line up behind a plane in a semi-rail-shooter mode and shoot him until he's gone. I thought the mode was ok, although it takes you out of the main battle a bit since you have to concentrate on the plane you're chasing. Some of the planes are designated TGT_LEAD and are only killable in DFM mode, which I do not like. The other thing about the fighter level is that the default Ace Combat controls have changed. If you look in the settings menu you'll see the defaults are called "Optimum." The old AC settings are in there if you want to switch back. I actually played the level in Optimum and didn't really mind. The Optimum control scheme, while not like a real airplane's scheme, is the same scheme used in space sims like X-Wing, TIE Fighter and Freespace 2.
The other level in the game is a helicopter level, which is a new thing for AC. You fly an Apache and give close air support to a Delta team rescuing a downed pilot being held by some rebels. I thought they did a good job with this level overall. You shoot infantry, SAMs, armored trucks, APCs, and eventually a few Hinds during the course of the mission. You've got rockets, Hellfires, and your machine gun. The control scheme is good, although it took me a few minutes to get used to it. The only other Apache game (or helicopter game for that matter) that I've tried is the 360 demo for Apache: Air Assault and I barely tried it so I can't even remember anything about it, so I'm not sure if the AC control scheme is close to what other games use or not. By the end of the level I was having fun hiding behind buildings and lining up on streets to mow down lines of incoming enemy vehicles. When you zoom in with your machine gun, the game somewhat resembles Apache gun camera videos. You can make out individual people, although not in a lot of detail, which I'm sure is on purpose.
Overall, I am excited after playing the demo. I already have the game pre-ordered but I would have definitely done so after playing the demo. Surprisingly, I am seeing a lot of negative comments both here on GB and over at Something Awful, mostly about DFM mode (understandable - it breaks a lot from the traditional AC formula) but also about helicopters. Maybe people just want to fly planes but I thought the helicopter level was well done so I don't mind it at all.