There were a couple of things that made this game really hard for me to play.
It's pretty brutal to damage the player from just walking into a barrier. And I wasn't sure what I could walk into without getting hurt. I could just walk over top of trees and cities and then when I run into a rock I lose my life somehow.
It seemed to me that the player spawns in random locations for the single player levels. The first time I played I started somewhere where I couldn't get to the objective in the first level. Another time, I spawed inside one of the rocks and I couldn't move and died in a couple seconds. I also spawed right next to the objective once and just walked right into it and won. There needs to be a definite starting zone.
It is also strange that you can walk off the edge of the world into a black area that drains your life very quickly. It should be a solid wall or maybe pac-man it to the other side of the level or something.
The controls for the plane are not very easy. It seems to me that up should make the plane accelerate forward instead of making it go up on the screen. Left and Right keys should turn the plane and Down should make it slow down.
I couldn't get past the second tutorial level because I kept spawning in areas where I couldn't complete the level, so I gave up. It seems to be a pretty cool game so far, but there are just so many things that make it hard for the player to continue playing at the moment. Keep working at it!