This is a good simple idea for a game. I think this game needs to give more feedback.

It would be nice to have an effect that showed where the mouse is clicking and how much area the attack from the mouse covers. 

Also the current sounds for enemies being destroyed are quiet and soft which does not match the event of destroying something big like an asteroid.

A great idea for a simple yet addictive gameplay! Personally, I'm not the most skilled player of these types of games, and I miss the ability to acquire passive upgrades through game progress (for example, increasing star durability or temporarily reducing asteroid speed at certain points). It's clear that this isn't the point of the game, but knowing that it's possible to beat it with time and a significant number of acquired upgrades, I'd like to give it more of a chance.