Well this is first game I ever play it plays by itself :)
I would really like to know if you made this logic or is from some asset? If you made it, then is very impresive, but questions is why completely let plane navigate alone? It coud be great that if you manage something before walls to collect, then game assist you, but if you didn't, you are all by yourself to make pass through. It is pretty, fun and if this is your first game, really great job!
Just one question, I let game for 15-20 minutes to play and have not seen that special mode you described here: "Survive as long as you can; and if you survive long enough, a special game mode is unlocked". How to get to that special mode?