this kept me entertained for about an hour even after i reached the end. excellent number go up game!!
i do want to mention that on the web build the asteroid being queue_freed caused a lag spike each time, and i think it might be because you are using gpu particles and not cpu particles. i'd highly recommend cpu particles next time to get a little better performance!
i also thought the big circle planet ui got in the way when trying to explode asteroids, especially during a storm. similarly i think when you're trying to destroy an asteroid that's floating over the planet directly you can set the control node's "mouse" property to be "pass (propagate up)"
these are otherwise very small nitpicks for an amazing game. great job!