Congratulations on your game, well done in just two hours!
Nice idea to adapt this type of shooter to a single button, it works very well.
You even managed to add particle effects that look very nice. I also really liked the "noise" (I don't know how to call it?) effect, it looks very nice and fits the game's atmosphere and story.
It is also cool that you have added different points depending on the size of the asteroid, which adds to the gameplay as you have to think about which one to shoot.