Keyboard, game pad or flight stick?
Mine's been downloaded since yesterday, but haven't had a chance to test it out. Gotta find and dust off a controller first.
Keyboard / mouse, which is probably the biggest problem. You use the mouse for weapons (LMB), defense "weapons" (RMB), and maneuvering. They invert the y-axis by default (pulling the mouse toward you climbs, away from you dives), which I promptly turned off - perfect for a joystick, but just not right for a mouse.
The biggest problem is the fact that W = boost (limited, depending on game mode think nitrous in racing games), S = air brake, and A/D = barrel roll right and left. When I have someone behind me firing at me, I find myself hitting A/D trying to turn sharply and doing a barrel roll instead, which screws me up.
Also, you guys need to realize that this is an ARCADE game, definitely nothing like a sim. The controls are very exaggerated compared to a sim, and obviously they are all kinds of power-ups and different weapons. Ever fired a shotgun from an aircraft? Yeah, you can do that here.
I did find one bug so far. Shift is default for a "loop" maneuver (climb sharply, go upside-down, come back down rightside-up). In unlimited boost games, your boost gets stuck off (unusable) until you die and respawn. Then it seems to work fine again.
Overall, if Plants Vs. Zombies gets a 10/10 as far as cheap games go, I'd give this one a 7/10. For $1.50 it's well worth it.