Jam games that use lots of mouth sounds? Excellent.
It took me a few runs to figure out that the asteroids also pushed back the big ship. But once I figured out the timing, it felt pretty great to "trick" the enemy into eating big ol rocks. Very satisfying. Well done on that!
I understand the need to bound the game, but I think those bounds could have been visualized more clearly to the player. Either have some sort of art change (darker clouds, ground, etc) or just lock the camera vertical movement so the movement bounds match the camera. You might also be able to use a wrapping quad to make the move space infinite vertically and then make ship spawn relative to player position to allow "infinite" up or down scrolling.
I might also make the big ship appear more quickly. On the first run, it's a cool little build up with the dialogue, but on subsequent runs it just seems to slow things down.
Overall, cool game. I had fun with it and was pleased by the little guitar riff for my eventual victory. Extra points for making a top down flying game that doesn't use shooting to win! Keep up the good work and congrats for making this in just a few days!