It's alright, and presents a challenge. My biggest complaint, actually, in an inability to scroll when the game is paused. Also, the difficulty curve is rather unbalanced, as 2-5 is by far the most difficult stage and most of the third train is comparatively easy.
I enjoy this game, though it is silly that my strategy went from "win in under the time limit" to "win before I blow myself up with my own weapons" in about three levels.
the platforming was passable and nothing that hasn't been done better else ware. It's artistic style was alright, but I don't think it is the bold statement on life that others do. Maybe I see a Simon-says game (how many you do right changes the ending) instead of a profound thesis that others see, but that's just me. I'm a cynic.
All in all, an alright game that's worth a play or two.
pro tip: the maximum range of guns is higher with the more agile plains. This means that small, agile plains can do long-rage attacks on slower craft with gun turrets without taking damage if they keep their distance.