Okay, I've 3 starred the Turbo Jet Diamond mission, 2 starred the Super Jet Pack Diamond Mission, and am too much of a wimp to try the Pedal Glider Diamond Mission. But I'm getting there.
With that said, is it me, or is this a seriously underrated game? I really don't think a lot of reviewers finished (aka 3 starred or perfected) this game. And there's a lot of things people wrote about that seem just plain wrong, like what people said about the music being "jazzy." I don't know if you could peg it down so easily. The music really complements the game well, from the very beginning of missions to the sound effects at the end. The music really seems to inspire this sense of wonder and freedom--- it seems like the musical equivalent of a Miyazaki film, specifically Porco Rosso or Kiki's Delivery Service. And there are so many subtle but complete touches, from the menu design, the way free flight opens up, the way the aircraft all control. In a very non-splashy, very subdued way, this is a really excellently crafted game. And the way this game really sinks its teeth into you and gets you addicted. Everyone I've talked to has agreed that by about the 3rd or 4th mission, it was pretty much it. You get hooked.
If I hadn't known better, I would've assumed this was an EAD or First-Party game (instead of being from Monster Games, ala ExciteTruck and Bots).