A two mission demo for the upcoming Ace Combat game is hitting Xbox Live today.
EDIT: Tried both missions, fighter and helicopter. The fighter mission was freaking fantastic! They've added a new element, which is called Dogfight mode. When you're within close enough range, a green circle will appear over the enemy. Hitting both bumpers will enter a zoomed-in mode where you're locked onto the enemy in a frantic chase. Guns are very useful here, obviously, but if you can keep a circle on him for long enough, it'll allow a more accurate (and possibly more damaging) missile fire. All the while, the enemy could be leading you toward buildings. It's very intense and a lot of fun.
I was very hopeful for the helicopter mission, but it was nowhere near as excellent as the fighter mission. The control was very smooth, but something gets a little lost in targeting (the game seems unable to decide between auto-lock and manual targeting being the default). Often you're targeting very small near pixels on the ground, so it can be less than clear what's going on when things get hectic. There also seem to be two forms of defense when missiles are coming at you: Shooting them down (which only works if you happen to target the guy who fired) or reality-straining barrel roll. I know copters can do this, but I seemed to be pulling barrel rolls way too frequently and from complete stand stills. I wish there was at least a little more variety.
That goes for the missions, too. The helicopter one felt very repetitious until I had to stop some guys with a hostage from making it to a truck. Otherwise it was very samey. The fighter sequence felt less so, though technically I suppose it was more so. The story was stronger there, so that may have helped.
Sound was great, and I actually didn't miss a lot of dialogue (something that happens waaaay to often in these types of games, IMO).
The graphics are really good, but I hope they improve some of the city ground textures before release.
Overall, I'm excited again for Ace Combat, though I wish the helicopter mode had me a little more interested. It's not bad, by any means, I just got my hopes up very high after the fighter part.