Thanks for taking the time to write this feedback ! Very well detailed and valuable.
I've really overshoot the scope for this one, my bad. I'm working on a collection menu with an info panel for each discovery to learn more about them, and will publish the update once the rating period is over(to be fair with the submission).
Also the original end-goal idea is to create more and more complex particles; going from elementary ones to atoms, to chemical molecules and so on until planets and galaxies ! I really want to keep the discovery / goal free experience for the player to learn by experimenting, but also don't want the to feel lost as you describe, what do you suggest me to do ?
PS: You can unlock the end-screen in the game by creating a Hydrogen Atom (create a Proton and catch an electron) but the proton creation is buggy in the submitted build, you'll have to wait my update (already fixed it)