I'm a simple guy: I'm always impressed when I see a full 3D game :D
The start is a bit difficult: jumping from clouds to clouds in order to get some woods may be a bit too hard for the beginning of the game, but I've managed to do it and I've built a cool plane!
I've used it, and it was quite cool (even if it was not balanced ^^). That's said, I could not find the iron, 'cause everything went to black after some times of fly: not sure if it was intentional or not ^^'
If I understand well it's your first time building a 3D game, so congrats to you!