This was really fun!
The visuals of this game where what caught my eye at first, and I really like the presentation it has overall. Having the musical chords build via clicking / orbiting / etc. was very satisfying. Surprisingly, because of this, crashing was kind of fun because it would make it resolve.
The controls for this are quite hard at first, but I knew that after while I would have the hang of it. I think some visual clarity (like drawing a line from the ship towards the mouse, with the length being the power) would help a lot at immediately understanding how to move, without needing to read. Especially for the Dual rocket segment, since I think the other rocket was inverted, but it was hard to always understand where it would go.
I love the idea of the secret worlds, and doing various puzzles to unlock and enter them. It almost gives an Outer Wilds vibe to it. I think if you were to make additions to this game, you could easily take some things from their book and create some mechanics that can be used anywhere, but you are only taught about it in a certain location. A full game with that in mind, and some story, would honestly be very unique.
The message of 'Journey not destination' is played pretty well here, since just getting to the end normally is pretty boring. But finding all the unique paths you can take to get there is fun. I think you conveyed this is a nice manner. As well as having the leaderboard be total distance travelled, instead of a fastest time. (Although, I would enjoy having a fastest time one too.. I want to zoom!)
There are some small adjustments that I would make, like giving the tether poles a slightly larger hitbox that what is shown. Since I would feel like I got it sometimes but didn't. It would also be nice to return back a screen, incase you accidentally go too far when trying to do a sequence.
If the map was larger, it would likely also benefit from being able to warp to any star location, or specific ones in general. Which would also allow you to design a more expansive map without having to worry about the time requirements to get to them. It also would've been nice to be able to open this map at any time, rather than just at the finish / start screen.
One thing to note, is that for web builds, ESC will not pause the game (assuming they are running in fullscreen). So it is nice to give an alternative key to do so (I usually do 'P').
Very neat game!