Expandable
HI,
the idear is not really bad, but if you want to creat a game where the time is necessary then it would be great if you put a timer into your game. Also its possible to fly through the boarder of the game, you should fix that. And last but not least, the spacebar is a key that nearly everybody would press (maybe to shot) so use a other key for your bonus level.
Good Luck for your next work.