We're glad you enjoyed our game and thank you for the feedback!
I believe the reason the enemies exploded before you saw them was because we made it so that the enemies were not damaged by the large asteroids but the smaller asteroid debris would damage them. It might be the case that you shot some bullets that blew up some asteroids and an enemy satellite passed through that "debris cloud" and was quickly destroyed.
I suppose an instant game over from hitting an asteroid is a bit harsh (perhaps it should instead do a lot of damage but not insta-kill). Again, thanks for your feedback :)