I remember playing this game. It's great to see you are still working on it!
I think i forgot to mention it in my review during the voting period, but the tutorial has too much text and not many people will read it. I would divide the story in different slides with a few lines of text so that it's easier to read (some contrast with the background would help too).
The new gameplay is challenging and quite fun, i would add a slight gravity effect to the game, so instead of a straight line, the player will make a curve towards the new asteroid. It's just adding a small force towards the direction of the next asteroid divided by the distance. It would look cool apart from making it a bit easier to aim.
Keep making games, the best way to learn is by doing. :)