Fair game...
Indeed, there are a lot of commands to use during missions, and the controls can get very complicated if you're not used to them. Fortunately, you can customize them to fit your style - and, after a few tries, I found a good control config to play with (very close to Ace Combat's). Also, there's a nice set of commands you can use to aid you in the battlefield, from evasive maneuvers to speed matching (which is VERY useful while you're chasing your tiny, nimble targets).
The HUD, though, is quite overloaded, in my opinion. There are a lot of enemy/ally markers on the screen and they are pretty laggy, the radar is useless (showing what's on your screen instead of what's around you) and the map has never helped me finding my objectives. I also experienced a lot of frame rate issues, which are really painful sometimes...
Project Sylpheed is not a bad game, but I had to persist a little before I could finally start to enjoy it. I would recommend it only to those who like flying around and shooting stuff down, like myself.