Kinda difficult. The "old planes and dogfighting" themes won't appeal to everyone.
This game garnered quite a bit of attention by being voted "Best Xbox Live Game" a couple years back. The story is almost something pulled out of the Golden Age of Hollywood-you're some famous '20s actor who's a fighter pilot on the side, flying antique plains against both old-school and more modern technological wonders of enemies.
The game looks really good graphics-wise, as the planes and other craft show ecxellent detail, as do the characters who fly them and play various other roles. There's also a lot of good dialogue in-flight between characters, often things like noticing mission critical details, exchanging orders, reporting problems, etc. The music is appropriate for the game but quickly gets dull. Controls are solid and responsive. The gameplay occurs at a good pace but for some people won't be fast enough, and also it's a little on the difficult side even with adjustable skill levels. Also, this type of game with "antique" planes slowly flying around won't appeal to everyone, especially those who prefer futuristic hi-tech or space combat-type shooters.
If you're into this kind of stuff, like the one who has lots of these flight sumulators on your PC for example, then you'll be right at home with this solid effort. Otherwise it's too old-looking and/or too slow-paced for everyone else, especially the typical adrenaline junky who needs lots of things to shoot at.