I personally thought that the bullets and ship should collide with the Earth. It would make the game really hard, but I personally think it would be fun. The meteor bug is weird, it happens at random intervals. It wasn't too bad as most of the time it might spawn right next to the Earth and you have a second. But there was two times while I was playing that it spawned on the Earth and immediately I took damage.
But you did a great job! The game is really polished and pretty damn fun!