Thank you! yeah, the difficulty in grabbing the small asteroids is definitely an issue. If I were to refine this game further, I'd definitely want to resolve that somehow. Maybe by snapping your grab to the nearest asteroid within a radius when you clicked, or something like that. I'd also have to make the tiny little things a lot easier to spot.
Using the big asteroid as a plough to shove the smaller asteroids is clever. The best way to overwhelm the AI is probably by using as many asteroids at once as possible, and that's probably one of the most reliable ways to do it.