This game can be either really easy or really hard, depending on the settings the player chooses.  There are two settings that really matter in terms of difficulty: difficulty level and control type.  Difficulty level determines how hard it is to take out enemy planes, how easily you get shot down, and how hard it is to evade enemy missiles.  Control type is found in the options menu (when you select a mission) and has an even bigger effect.  With the novice (defalt) controls, your plane automatically turns back to level after turns and you can't control yaw (rotational turn left and right) or invert.  On expert mode, you can do anything: barrel roll, reverse illemans, REAL break turns, etc.  The latter makes the already difficult levels nearly impossible (except for dogfights, which are much easier with expert controls).  Secondly, the levels are incredibly detailed; at one point, you fly into an enemy base that is in caverns in a mountain.  It feels like mission impossible.  Finally, I don't know what people are talking about when they say that the plane you choose doesn't matter.  It does.  Just trust me.  I would recommend this game to almost anyone.  It does a good job of making levels hard for better replay value and allows you to some crazy moves with experts controls.  Its best trait is that you can play it on two different levels: a plane-based shoot-em-up or a combat intensive flight-sim.