Like the gameplay and the music fits well.
As for the feedback, it's kinda awkward for me to play because usually, most games move with wasd and aim with arrow for this kind of game. An option to reverse the control would be wonderful. For the shield, I think making it push the asteroid further rather than destroying it will be great, as the asteroid won't drop the coin when destroyed by the shield which is wasted. And rather than time- gated end, maybe add another game mode choice where the game end when the base is destroyed is favorable.
Well, That's all my opinion. Good Game!